hunspell(5) File Formats Manual hunspell(5)
NAME
hunspell - format of Hunspell dictionaries and affix files
DESCRIPTION
Hunspell(1) Hunspell requires two files to define the way a language is
being spell checked: a dictionary file containing words and applicable
flags, and an affix file that specifies how these flags will control
spell checking. An optional file is the personal dictionary file.
Dictionary file
A dictionary file (*.dic) contains a list of words, one per line. The
first line of the dictionaries (except personal dictionaries) contains
the approximate word count (for optimal hash memory size). Each word
may optionally be followed by a slash ("/") and one or more flags,
which represents the word attributes, for example affixes.
Note: Dictionary words can contain also slashes when escaped like "\/"
syntax.
It's worth to add not only words, but word pairs to the dictionary to
get correct suggestions for common misspellings with missing space, as
in the following example, for the bad "alot" and "inspite" (see also
"REP" and field "ph:" about correct suggestions for common mis-
spellings):
3
word
a lot
in spite
Personal dictionary file
Personal dictionaries are simple word lists. Asterisk at the first
character position signs prohibition. A second word separated by a
slash sets the affixation.
foo
Foo/Simpson
*bar
In this example, "foo" and "Foo" are personal words, plus Foo will be
recognized with affixes of Simpson (Foo's etc.) and bar is a forbidden
word.
Short example
Dictionary file:
3
hello
try/B
work/AB
The flags B and A specify attributes of these words.
Affix file:
SET UTF-8
TRY esianrtolcdugmphbyfvkwzESIANRTOLCDUGMPHBYFVKWZ'
REP 2
REP f ph
REP ph f
PFX A Y 1
PFX A 0 re .
SFX B Y 2
SFX B 0 ed [^y]
SFX B y ied y
In the affix file, prefix A and suffix B have been defined. Flag A de-
fines a `re-' prefix. Class B defines two `-ed' suffixes. First B suf-
fix can be added to a word if the last character of the word isn't `y'.
Second suffix can be added to the words terminated with an `y'.
All accepted words with this dictionary and affix combination are:
"hello", "try", "tried", "work", "worked", "rework", "reworked".
AFFIX FILE GENERAL OPTIONS
Hunspell source distribution contains more than 80 examples for option
usage.
SET encoding
Set character encoding of words and morphemes in affix and dic-
tionary files. Possible values: UTF-8, ISO8859-1 - ISO8859-10,
ISO8859-13 - ISO8859-15, KOI8-R, KOI8-U, cp1251, ISCII-DEVANA-
GARI.
SET UTF-8
FLAG value
Set flag type. Default type is the extended ASCII (8-bit) char-
acter. `UTF-8' parameter sets UTF-8 encoded Unicode character
flags. The `long' value sets the double extended ASCII charac-
ter flag type, the `num' sets the decimal number flag type. Dec-
imal flags numbered from 1 to 65000, and in flag fields are sep-
arated by comma. BUG: UTF-8 flag type doesn't work on ARM plat-
form.
FLAG long
COMPLEXPREFIXES
Set twofold prefix stripping (but single suffix stripping) eg.
for morphologically complex languages with right-to-left writing
system.
LANG langcode
Set language code for language-specific functions of Hunspell.
Use it to activate special casing of Azeri (LANG az), Turkish
(LANG tr) and Crimean Tatar (LANG crh), also not generalized
syllable-counting compounding rules of Hungarian (LANG hu).
IGNORE characters
Sets characters to ignore dictionary words, affixes and input
words. Useful for optional characters, as Arabic (harakat) or
Hebrew (niqqud) diacritical marks (see tests/ignore.* test dic-
tionary in Hunspell distribution).
AF number_of_flag_vector_aliases
AF flag_vector
Hunspell can substitute affix flag sets with ordinal numbers in
affix rules (alias compression, see makealias tool). First exam-
ple with alias compression:
3
hello
try/1
work/2
AF definitions in the affix file:
AF 2
AF A
AF AB
It is equivalent of the following dic file:
3
hello
try/A
work/AB
See also tests/alias* examples of the source distribution.
Note I: If affix file contains the FLAG parameter, define it before the
AF definitions.
Note II: Use makealias utility in Hunspell distribution to compress aff
and dic files.
AM number_of_morphological_aliases
AM morphological_fields
Hunspell can substitute also morphological data with ordinal
numbers in affix rules (alias compression). See tests/alias*
examples.
AFFIX FILE OPTIONS FOR SUGGESTION
Suggestion parameters can optimize the default n-gram (similarity
search in the dictionary words based on the common 1, 2, 3, 4-character
length common character-sequences), character swap and deletion sugges-
tions of Hunspell. REP is suggested to fix the typical and especially
bad language specific bugs, because the REP suggestions have the high-
est priority in the suggestion list. PHONE is for languages with not
pronunciation based orthography.
For short common misspellings, it's important to use the ph: field (see
later) to give the best suggestions.
KEY characters_separated_by_vertical_line_optionally
Hunspell searches and suggests words with one different charac-
ter replaced by a neighbor KEY character. Not neighbor charac-
ters in KEY string separated by vertical line characters. Sug-
gested KEY parameters for QWERTY and Dvorak keyboard layouts:
KEY qwertyuiop|asdfghjkl|zxcvbnm
KEY pyfgcrl|aeouidhtns|qjkxbmwvz
Using the first QWERTY layout, Hunspell suggests "nude" and "node" for
"*nide". A character may have more neighbors, too:
KEY qwertzuop|yxcvbnm|qaw|say|wse|dsx|sy|edr|fdc|dx|rft|gfv|fc|tgz|hgb|gv|zhu|jhn|hb|uji|kjm|jn|iko|lkm
TRY characters
Hunspell can suggest right word forms, when they differ from the
bad input word by one TRY character. The parameter of TRY is
case sensitive.
NOSUGGEST flag
Words signed with NOSUGGEST flag are not suggested (but still
accepted when typed correctly). Proposed flag for vulgar and ob-
scene words (see also SUBSTANDARD).
MAXCPDSUGS num
Set max. number of suggested compound words generated by com-
pound rules. The number of the suggested compound words may be
greater from the same 1-character distance type.
MAXNGRAMSUGS num
Set max. number of n-gram suggestions. Value 0 switches off the
n-gram suggestions (see also MAXDIFF).
MAXDIFF [0-10]
Set the similarity factor for the n-gram based suggestions (5 =
default value; 0 = fewer n-gram suggestions, but min. 1; 10 =
MAXNGRAMSUGS n-gram suggestions).
ONLYMAXDIFF
Remove all bad n-gram suggestions (default mode keeps one, see
MAXDIFF).
NOSPLITSUGS
Disable word suggestions with spaces.
SUGSWITHDOTS
Add dot(s) to suggestions, if input word terminates in dot(s).
(Not for LibreOffice dictionaries, because LibreOffice has an
automatic dot expansion mechanism.)
REP number_of_replacement_definitions
REP what replacement
This table specifies modifications to try first. First REP is
the header of this table and one or more REP data line are fol-
lowing it. With this table, Hunspell can suggest the right
forms for the typical spelling mistakes when the incorrect form
differs by more than 1 letter from the right form (see also
"ph:"). The search string supports the regex boundary signs (^
and $). For example a possible English replacement table defi-
nition to handle misspelled consonants:
REP 5
REP f ph
REP ph f
REP tion$ shun
REP ^cooccurr co-occurr
REP ^alot$ a_lot
Note I: It's very useful to define replacements for the most typical
one-character mistakes, too: with REP you can add higher priority to a
subset of the TRY suggestions (suggestion list begins with the REP sug-
gestions).
Note II: Suggesting separated words, specify spaces with underlines:
REP 1
REP onetwothree one_two_three
Note III: Replacement table can be used for a stricter compound word
checking with the option CHECKCOMPOUNDREP.
MAP number_of_map_definitions
MAP string_of_related_chars_or_parenthesized_character_sequences
We can define language-dependent information on characters and
character sequences that should be considered related (i.e.
nearer than other chars not in the set) in the affix file (.aff)
by a map table. With this table, Hunspell can suggest the right
forms for words, which incorrectly choose the wrong letter or
letter groups from a related set more than once in a word (see
REP).
For example a possible mapping could be for the German umlauted
ü versus the regular u; the word Frühstück really should be
written with umlauted u's and not regular ones
MAP 1
MAP uü
Use parenthesized groups for character sequences (eg. for composed Uni-
code characters):
MAP 3
MAP ß(ss) (character sequence)
MAP fi(fi) ("fi" compatibility characters for Unicode fi ligature)
MAP (ọ́)o (composed Unicode character: ó with bottom dot)
PHONE number_of_phone_definitions
PHONE what replacement
PHONE uses a table-driven phonetic transcription algorithm bor-
rowed from Aspell. It is useful for languages with not pronunci-
ation based orthography. You can add a full alphabet conversion
and other rules for conversion of special letter sequences. For
detailed documentation see http://aspell.net/man-html/Phonetic-
Code.html. Note: Multibyte UTF-8 characters have not worked
with bracket expression yet. Dash expression has signed bytes
and not UTF-8 characters yet.
WARN flag
This flag is for rare words, which are also often spelling mis-
takes, see option -r of command line Hunspell and FORBIDWARN.
FORBIDWARN
Words with flag WARN aren't accepted by the spell checker using
this parameter.
OPTIONS FOR COMPOUNDING
BREAK number_of_break_definitions
BREAK character_or_character_sequence
Define new break points for breaking words and checking word
parts separately. Use ^ and $ to delete characters at end and
start of the word. Rationale: useful for compounding with join-
ing character or strings (for example, hyphen in English and
German or hyphen and n-dash in Hungarian). Dashes are often bad
break points for tokenization, because compounds with dashes may
contain not valid parts, too.) With BREAK, Hunspell can check
both side of these compounds, breaking the words at dashes and
n-dashes:
BREAK 2
BREAK -
BREAK -- # n-dash
Breaking are recursive, so foo-bar, bar-foo and foo-foo--bar-bar would
be valid compounds. Note: The default word break of Hunspell is equiv-
alent of the following BREAK definition:
BREAK 3
BREAK -
BREAK ^-
BREAK -$
Hunspell doesn't accept the "-word" and "word-" forms by this BREAK
definition:
BREAK 1
BREAK -
Switching off the default values:
BREAK 0
Note II: COMPOUNDRULE is better for handling dashes and other compound
joining characters or character strings. Use BREAK, if you want to
check words with dashes or other joining characters and there is no
time or possibility to describe precise compound rules with COM-
POUNDRULE (COMPOUNDRULE handles only the suffixation of the last word
part of a compound word).
Note III: For command line spell checking of words with extra charac-
ters, set WORDCHARS parameters: WORDCHARS --- (see tests/break.*) exam-
ple
COMPOUNDRULE number_of_compound_definitions
COMPOUNDRULE compound_pattern
Define custom compound patterns with a regex-like syntax. The
first COMPOUNDRULE is a header with the number of the following
COMPOUNDRULE definitions. Compound patterns consist compound
flags, parentheses, star and question mark meta characters. A
flag followed by a `*' matches a word sequence of 0 or more
matches of words signed with this compound flag. A flag fol-
lowed by a `?' matches a word sequence of 0 or 1 matches of a
word signed with this compound flag. See tests/compound*.* ex-
amples.
Note: en_US dictionary of OpenOffice.org uses COMPOUNDRULE for
ordinal number recognition (1st, 2nd, 11th, 12th, 22nd, 112th,
1000122nd etc.).
Note II: In the case of long and numerical flag types use only
parenthesized flags: (1500)*(2000)?
Note III: COMPOUNDRULE flags work completely separately from the
compounding mechanisms using COMPOUNDFLAG, COMPOUNDBEGIN, etc.
compound flags. (Use these flags on different entries for
words).
COMPOUNDMIN num
Minimum length of words used for compounding. Default value is
3 letters.
COMPOUNDFLAG flag
Words signed with COMPOUNDFLAG may be in compound words (except
when word shorter than COMPOUNDMIN). Affixes with COMPOUNDFLAG
also permits compounding of affixed words.
COMPOUNDBEGIN flag
Words signed with COMPOUNDBEGIN (or with a signed affix) may be
first elements in compound words.
COMPOUNDLAST flag
Words signed with COMPOUNDLAST (or with a signed affix) may be
last elements in compound words.
COMPOUNDMIDDLE flag
Words signed with COMPOUNDMIDDLE (or with a signed affix) may be
middle elements in compound words.
ONLYINCOMPOUND flag
Suffixes signed with ONLYINCOMPOUND flag may be only inside of
compounds (Fuge-elements in German, fogemorphemes in Swedish).
ONLYINCOMPOUND flag works also with words (see tests/onlyincom-
pound.*). Note: also valuable to flag compounding parts which
are not correct as a word by itself.
COMPOUNDPERMITFLAG flag
Prefixes are allowed at the beginning of compounds, suffixes are
allowed at the end of compounds by default. Affixes with COM-
POUNDPERMITFLAG may be inside of compounds.
COMPOUNDFORBIDFLAG flag
Suffixes with this flag forbid compounding of the affixed word.
Dictionary words with this flag are removed from the beginning
and middle of compound words, overriding the effect of COMPOUND-
PERMITFLAG.
COMPOUNDMORESUFFIXES
Allow twofold suffixes within compounds.
COMPOUNDROOT flag
COMPOUNDROOT flag signs the compounds in the dictionary (Now it
is used only in the Hungarian language specific code).
COMPOUNDWORDMAX number
Set maximum word count in a compound word. (Default is unlim-
ited.)
CHECKCOMPOUNDDUP
Forbid word duplication in compounds (e.g. foofoo).
CHECKCOMPOUNDREP
Forbid compounding, if the (usually bad) compound word may be a
non-compound word with a REP fault. Useful for languages with
`compound friendly' orthography.
CHECKCOMPOUNDCASE
Forbid upper case characters at word boundaries in compounds.
CHECKCOMPOUNDTRIPLE
Forbid compounding, if compound word contains triple repeating
letters (e.g. foo|ox or xo|oof). Bug: missing multi-byte charac-
ter support in UTF-8 encoding (works only for 7-bit ASCII char-
acters).
SIMPLIFIEDTRIPLE
Allow simplified 2-letter forms of the compounds forbidden by
CHECKCOMPOUNDTRIPLE. It's useful for Swedish and Norwegian (and
for the old German orthography: Schiff|fahrt -> Schiffahrt).
CHECKCOMPOUNDPATTERN number_of_checkcompoundpattern_definitions
CHECKCOMPOUNDPATTERN endchars[/flag] beginchars[/flag] [replacement]
Forbid compounding, if the first word in the compound ends with
endchars, and next word begins with beginchars and (optionally)
they have the requested flags. The optional replacement parame-
ter allows simplified compound form.
The special "endchars" pattern 0 (zero) limits the rule to the
unmodified stems (stems and stems with zero affixes):
CHECKCOMPOUNDPATTERN 0/x /y
Note: COMPOUNDMIN doesn't work correctly with the compound word alter-
nation, so it may need to set COMPOUNDMIN to lower value.
FORCEUCASE flag
Last word part of a compound with flag FORCEUCASE forces capi-
talization of the whole compound word. Eg. Dutch word "straat"
(street) with FORCEUCASE flags will allowed only in capitalized
compound forms, according to the Dutch spelling rules for proper
names.
COMPOUNDSYLLABLE max_syllable vowels
Need for special compounding rules in Hungarian. First parame-
ter is the maximum syllable number, that may be in a compound,
if words in compounds are more than COMPOUNDWORDMAX. Second pa-
rameter is the list of vowels (for calculating syllables).
SYLLABLENUM flags
Need for special compounding rules in Hungarian.
AFFIX FILE OPTIONS FOR AFFIX CREATION
PFX flag cross_product number
PFX flag stripping prefix [condition [morphological_fields...]]
SFX flag cross_product number
SFX flag stripping suffix [condition [morphological_fields...]]
An affix is either a prefix or a suffix attached to root words
to make other words. We can define affix classes with arbitrary
number affix rules. Affix classes are signed with affix flags.
The first line of an affix class definition is the header. The
fields of an affix class header:
(0) Option name (PFX or SFX)
(1) Flag (name of the affix class)
(2) Cross product (permission to combine prefixes and suffixes).
Possible values: Y (yes) or N (no)
(3) Line count of the following rules.
Fields of an affix rules:
(0) Option name
(1) Flag
(2) stripping characters from beginning (at prefix rules) or end
(at suffix rules) of the word
(3) affix (optionally with flags of continuation classes, sepa-
rated by a slash)
(4) condition.
Zero stripping or affix are indicated by zero. Zero condition is
indicated by dot. Condition is a simplified, regular expres-
sion-like pattern, which must be met before the affix can be ap-
plied. (Dot signs an arbitrary character. Characters in braces
sign an arbitrary character from the character subset. Dash
hasn't got special meaning, but circumflex (^) next the first
brace sets the complementer character set.)
(5) Optional morphological fields separated by spaces or tabula-
tors.
AFFIX FILE OTHER OPTIONS
CIRCUMFIX flag
Affixes signed with CIRCUMFIX flag may be on a word when this
word also has a prefix with CIRCUMFIX flag and vice versa (see
circumfix.* test files in the source distribution).
FORBIDDENWORD flag
This flag signs forbidden word form. Because affixed forms are
also forbidden, we can subtract a subset from set of the ac-
cepted affixed and compound words. Note: usefull to forbid er-
roneous words, generated by the compounding mechanism.
FULLSTRIP
With FULLSTRIP, affix rules can strip full words, not only one
less characters, before adding the affixes, see fullstrip.* test
files in the source distribution). Note: conditions may be word
length without FULLSTRIP, too.
KEEPCASE flag
Forbid uppercased and capitalized forms of words signed with
KEEPCASE flags. Useful for special orthographies (measurements
and currency often keep their case in uppercased texts) and
writing systems (e.g. keeping lower case of IPA characters).
Also valuable for words erroneously written in the wrong case.
Note: With CHECKSHARPS declaration, words with sharp s and KEEP-
CASE flag may be capitalized and uppercased, but uppercased
forms of these words may not contain sharp s, only SS. See ger-
mancompounding example in the tests directory of the Hunspell
distribution.
ICONV number_of_ICONV_definitions
ICONV pattern pattern2
Define input conversion table. Note: useful to convert one type
of quote to another one, or change ligature.
OCONV number_of_OCONV_definitions
OCONV pattern pattern2
Define output conversion table.
LEMMA_PRESENT flag
Deprecated. Use "st:" field instead of LEMMA_PRESENT.
NEEDAFFIX flag
This flag signs virtual stems in the dictionary, words only
valid when affixed. Except, if the dictionary word has a
homonym or a zero affix. NEEDAFFIX works also with prefixes and
prefix + suffix combinations (see tests/needaffix5.*).
PSEUDOROOT flag
Deprecated. (Former name of the NEEDAFFIX option.)
SUBSTANDARD flag
SUBSTANDARD flag signs affix rules and dictionary words (allo-
morphs) not used in morphological generation and root words re-
moved from suggestion. See also NOSUGGEST.
WORDCHARS characters
WORDCHARS extends tokenizer of Hunspell command line interface
with additional word character. For example, dot, dash, n-dash,
numbers, percent sign are word character in Hungarian.
CHECKSHARPS
SS letter pair in uppercased (German) words may be upper case
sharp s (ß). Hunspell can handle this special casing with the
CHECKSHARPS declaration (see also KEEPCASE flag and tests/ger-
mancompounding example) in both spelling and suggestion.
Morphological analysis
Hunspell's dictionary items and affix rules may have optional space or
tabulator separated morphological description fields, started with
3-character (two letters and a colon) field IDs:
word/flags po:noun is:nom
Example: We define a simple resource with morphological informations, a
derivative suffix (ds:) and a part of speech category (po:):
Affix file:
SFX X Y 1
SFX X 0 able . ds:able
Dictionary file:
drink/X po:verb
Test file:
drink
drinkable
Test:
$ analyze test.aff test.dic test.txt
> drink
analyze(drink) = po:verb
stem(drink) = po:verb
> drinkable
analyze(drinkable) = po:verb ds:able
stem(drinkable) = drinkable
You can see in the example, that the analyzer concatenates the morpho-
logical fields in item and arrangement style.
Optional data fields
Default morphological and other IDs (used in suggestion, stemming and
morphological generation):
ph: Alternative transliteration for better suggestions, ie. mis-
spellings related to the special orthography and pronunciation
of the word. The best way to handle common misspellings, so it's
worth to add ph: field to the most affected few thousand dictio-
nary words (or word pairs etc.) to get correct suggestions for
their misspellings.
For example:
Wednesday ph:wendsay ph:wensday
Marseille ph:maarsayl
Hunspell adds all ph: transliterations to the inner REP table, so it
will always suggest the correct word for the specified misspellings
with the highest priority.
The previous example is equivalent of the following REP definition:
REP 6
REP wendsay Wednesday
REP Wendsay Wednesday
REP wensday Wednesday
REP Wensday Wednesday
REP maarsayl Marseille
REP Maarsayl Marseille
The asterisk at the end of the ph: pattern means stripping the termi-
nating character both from the pattern and the word in the associated
REP rule:
pretty ph:prity*
will result
REP 1
REP prit prett
REP rule, resulting the following correct suggestions
*prity -> pretty
*pritier -> prettier
*pritiest -> prettiest
Moreover, ph: fields can handle suggestions with more than two words,
also different suggestions for the same misspelling:
do not know ph:dunno
don't know ph:dunno
results
*dunno -> do not know, don't know
Note: if available, ph: is used in n-gram similarity, too.
The ASCII arrow "->" in a ph: pattern means a REP rule (see REP), cre-
ating arbitrary replacement rule associated to the dictionary item:
happy/B ph:hepy ph:hepi->happi
results
*hepy -> happy
*hepiest -> happiest
st: Stem. Optional: default stem is the dictionary item in morpho-
logical analysis. Stem field is useful for virtual stems (dic-
tionary words with NEEDAFFIX flag) and morphological exceptions
instead of new, single used morphological rules.
feet st:foot is:plural
mice st:mouse is:plural
teeth st:tooth is:plural
Word forms with multiple stems need multiple dictionary items:
lay po:verb st:lie is:past_2
lay po:verb is:present
lay po:noun
al: Allomorph(s). A dictionary item is the stem of its allomorphs.
Morphological generation needs stem, allomorph and affix fields.
sing al:sang al:sung
sang st:sing
sung st:sing
po: Part of speech category.
ds: Derivational suffix(es). Stemming doesn't remove derivational
suffixes. Morphological generation depends on the order of the
suffix fields.
In affix rules:
SFX Y Y 1
SFX Y 0 ly . ds:ly_adj
In the dictionary:
ably st:able ds:ly_adj
able al:ably
is: Inflectional suffix(es). All inflectional suffixes are removed
by stemming. Morphological generation depends on the order of
the suffix fields.
feet st:foot is:plural
ts: Terminal suffix(es). Terminal suffix fields are inflectional
suffix fields "removed" by additional (not terminal) suffixes.
Useful for zero morphemes and affixes removed by splitting
rules.
work/D ts:present
SFX D Y 2
SFX D 0 ed . is:past_1
SFX D 0 ed . is:past_2
Typical example of the terminal suffix is the zero morpheme of the nom-
inative case.
sp: Surface prefix. Temporary solution for adding prefixes to the
stems and generated word forms. See tests/morph.* example.
pa: Parts of the compound words. Output fields of morphological
analysis for stemming.
dp: Planned: derivational prefix.
ip: Planned: inflectional prefix.
tp: Planned: terminal prefix.
Twofold suffix stripping
Ispell's original algorithm strips only one suffix. Hunspell can strip
another one yet (or a plus prefix in COMPLEXPREFIXES mode).
The twofold suffix stripping is a significant improvement in handling
of immense number of suffixes, that characterize agglutinative lan-
guages.
A second `s' suffix (affix class Y) will be the continuation class of
the suffix `able' in the following example:
SFX Y Y 1
SFX Y 0 s .
SFX X Y 1
SFX X 0 able/Y .
Dictionary file:
drink/X
Test file:
drink
drinkable
drinkables
Test:
$ hunspell -m -d test <test.txt
drink st:drink
drinkable st:drink fl:X
drinkables st:drink fl:X fl:Y
Theoretically with the twofold suffix stripping needs only the square
root of the number of suffix rules, compared with a Hunspell implemen-
tation. In our practice, we could have elaborated the Hungarian inflec-
tional morphology with twofold suffix stripping.
Extended affix classes
Hunspell can handle more than 65000 affix classes. There are three new
syntax for giving flags in affix and dictionary files.
FLAG long command sets 2-character flags:
FLAG long
SFX Y1 Y 1
SFX Y1 0 s 1
Dictionary record with the Y1, Z3, F? flags:
foo/Y1Z3F?
FLAG num command sets numerical flags separated by comma:
FLAG num
SFX 65000 Y 1
SFX 65000 0 s 1
Dictionary example:
foo/65000,12,2756
The third one is the Unicode character flags.
Homonyms
Hunspell's dictionary can contain repeating elements that are homonyms:
work/A po:verb
work/B po:noun
An affix file:
SFX A Y 1
SFX A 0 s . sf:sg3
SFX B Y 1
SFX B 0 s . is:plur
Test file:
works
Test:
$ hunspell -d test -m <testwords
work st:work po:verb is:sg3
work st:work po:noun is:plur
This feature also gives a way to forbid illegal prefix/suffix combina-
tions.
Prefix--suffix dependencies
An interesting side-effect of multi-step stripping is, that the appro-
priate treatment of circumfixes now comes for free. For instance, in
Hungarian, superlatives are formed by simultaneous prefixation of leg-
and suffixation of -bb to the adjective base. A problem with the one-
level architecture is that there is no way to render lexical licensing
of particular prefixes and suffixes interdependent, and therefore in-
correct forms are recognized as valid, i.e. *legvén = leg + vén `old'.
Until the introduction of clusters, a special treatment of the superla-
tive had to be hardwired in the earlier HunSpell code. This may have
been legitimate for a single case, but in fact prefix--suffix depen-
dences are ubiquitous in category-changing derivational patterns (cf.
English payable, non-payable but *non-pay or drinkable, undrinkable but
*undrink). In simple words, here, the prefix un- is legitimate only if
the base drink is suffixed with -able. If both these patters are han-
dled by on-line affix rules and affix rules are checked against the
base only, there is no way to express this dependency and the system
will necessarily over- or undergenerate.
In next example, suffix class R have got a prefix `continuation' class
(class P).
PFX P Y 1
PFX P 0 un . [prefix_un]+
SFX S Y 1
SFX S 0 s . +PL
SFX Q Y 1
SFX Q 0 s . +3SGV
SFX R Y 1
SFX R 0 able/PS . +DER_V_ADJ_ABLE
Dictionary:
2
drink/RQ [verb]
drink/S [noun]
Morphological analysis:
> drink
drink[verb]
drink[noun]
> drinks
drink[verb]+3SGV
drink[noun]+PL
> drinkable
drink[verb]+DER_V_ADJ_ABLE
> drinkables
drink[verb]+DER_V_ADJ_ABLE+PL
> undrinkable
[prefix_un]+drink[verb]+DER_V_ADJ_ABLE
> undrinkables
[prefix_un]+drink[verb]+DER_V_ADJ_ABLE+PL
> undrink
Unknown word.
> undrinks
Unknown word.
Circumfix
Conditional affixes implemented by a continuation class are not enough
for circumfixes, because a circumfix is one affix in morphology. We
also need CIRCUMFIX option for correct morphological analysis.
# circumfixes: ~ obligate prefix/suffix combinations
# superlative in Hungarian: leg- (prefix) AND -bb (suffix)
# nagy, nagyobb, legnagyobb, legeslegnagyobb
# (great, greater, greatest, most greatest)
CIRCUMFIX X
PFX A Y 1
PFX A 0 leg/X .
PFX B Y 1
PFX B 0 legesleg/X .
SFX C Y 3
SFX C 0 obb . +COMPARATIVE
SFX C 0 obb/AX . +SUPERLATIVE
SFX C 0 obb/BX . +SUPERSUPERLATIVE
Dictionary:
1
nagy/C [MN]
Analysis:
> nagy
nagy[MN]
> nagyobb
nagy[MN]+COMPARATIVE
> legnagyobb
nagy[MN]+SUPERLATIVE
> legeslegnagyobb
nagy[MN]+SUPERSUPERLATIVE
Compounds
Allowing free compounding yields decrease in precision of recognition,
not to mention stemming and morphological analysis. Although lexical
switches are introduced to license compounding of bases by Ispell, this
proves not to be restrictive enough. For example:
# affix file
COMPOUNDFLAG X
2
foo/X
bar/X
With this resource, foobar and barfoo also are accepted words.
This has been improved upon with the introduction of direction-sensi-
tive compounding, i.e., lexical features can specify separately whether
a base can occur as leftmost or rightmost constituent in compounds.
This, however, is still insufficient to handle the intricate patterns
of compounding, not to mention idiosyncratic (and language specific)
norms of hyphenation.
The Hunspell algorithm currently allows any affixed form of words,
which are lexically marked as potential members of compounds. Hunspell
improved this, and its recursive compound checking rules makes it pos-
sible to implement the intricate spelling conventions of Hungarian com-
pounds. For example, using COMPOUNDWORDMAX, COMPOUNDSYLLABLE, COMPOUND-
ROOT, SYLLABLENUM options can be set the noteworthy Hungarian `6-3'
rule. Further example in Hungarian, derivate suffixes often modify
compounding properties. Hunspell allows the compounding flags on the
affixes, and there are two special flags (COMPOUNDPERMITFLAG and (COM-
POUNDFORBIDFLAG) to permit or prohibit compounding of the derivations.
Suffixes with this flag forbid compounding of the affixed word.
We also need several Hunspell features for handling German compounding:
# German compounding
# set language to handle special casing of German sharp s
LANG de_DE
# compound flags
COMPOUNDBEGIN U
COMPOUNDMIDDLE V
COMPOUNDEND W
# Prefixes are allowed at the beginning of compounds,
# suffixes are allowed at the end of compounds by default:
# (prefix)?(root)+(affix)?
# Affixes with COMPOUNDPERMITFLAG may be inside of compounds.
COMPOUNDPERMITFLAG P
# for German fogemorphemes (Fuge-element)
# Hint: ONLYINCOMPOUND is not required everywhere, but the
# checking will be a little faster with it.
ONLYINCOMPOUND X
# forbid uppercase characters at compound word bounds
CHECKCOMPOUNDCASE
# for handling Fuge-elements with dashes (Arbeits-)
# dash will be a special word
COMPOUNDMIN 1
WORDCHARS -
# compound settings and fogemorpheme for `Arbeit'
SFX A Y 3
SFX A 0 s/UPX .
SFX A 0 s/VPDX .
SFX A 0 0/WXD .
SFX B Y 2
SFX B 0 0/UPX .
SFX B 0 0/VWXDP .
# a suffix for `Computer'
SFX C Y 1
SFX C 0 n/WD .
# for forbid exceptions (*Arbeitsnehmer)
FORBIDDENWORD Z
# dash prefix for compounds with dash (Arbeits-Computer)
PFX - Y 1
PFX - 0 -/P .
# decapitalizing prefix
# circumfix for positioning in compounds
PFX D Y 29
PFX D A a/PX A
PFX D Ä ä/PX Ä
.
.
PFX D Y y/PX Y
PFX D Z z/PX Z
Example dictionary:
4
Arbeit/A-
Computer/BC-
-/W
Arbeitsnehmer/Z
Accepted compound compound words with the previous resource:
Computer
Computern
Arbeit
Arbeits-
Computerarbeit
Computerarbeits-
Arbeitscomputer
Arbeitscomputern
Computerarbeitscomputer
Computerarbeitscomputern
Arbeitscomputerarbeit
Computerarbeits-Computer
Computerarbeits-Computern
Not accepted compoundings:
computer
arbeit
Arbeits
arbeits
ComputerArbeit
ComputerArbeits
Arbeitcomputer
ArbeitsComputer
Computerarbeitcomputer
ComputerArbeitcomputer
ComputerArbeitscomputer
Arbeitscomputerarbeits
Computerarbeits-computer
Arbeitsnehmer
This solution is still not ideal, however, and will be replaced by a
pattern-based compound-checking algorithm which is closely integrated
with input buffer tokenization. Patterns describing compounds come as a
separate input resource that can refer to high-level properties of con-
stituent parts (e.g. the number of syllables, affix flags, and contain-
ment of hyphens). The patterns are matched against potential segmenta-
tions of compounds to assess wellformedness.
Unicode character encoding
Both Ispell and Myspell use 8-bit ASCII character encoding, which is a
major deficiency when it comes to scalability. Although a language
like Hungarian has a standard ASCII character set (ISO 8859-2), it
fails to allow a full implementation of Hungarian orthographic conven-
tions. For instance, the '--' symbol (n-dash) is missing from this
character set contrary to the fact that it is not only the official
symbol to delimit parenthetic clauses in the language, but it can be in
compound words as a special 'big' hyphen.
MySpell has got some 8-bit encoding tables, but there are languages
without standard 8-bit encoding, too. For example, a lot of African
languages have non-latin or extended latin characters.
Similarly, using the original spelling of certain foreign names like
Ångström or Molière is encouraged by the Hungarian spelling norm, and,
since characters 'Å' and 'è' are not part of ISO 8859-2, when they com-
bine with inflections containing characters only in ISO 8859-2 (like
elative -ből, allative -től or delative -ről with double acute), these
result in words (like Ångströmről or Molière-től.) that can not be en-
coded using any single ASCII encoding scheme.
The problems raised in relation to 8-bit ASCII encoding have long been
recognized by proponents of Unicode. It is clear that trading effi-
ciency for encoding-independence has its advantages when it comes a
truly multi-lingual application. There is implemented a memory and time
efficient Unicode handling in Hunspell. In non-UTF-8 character encod-
ings Hunspell works with the original 8-bit strings. In UTF-8 encoding,
affixes and words are stored in UTF-8, during the analysis are handled
in mostly UTF-8, under condition checking and suggestion are converted
to UTF-16. Unicode text analysis and spell checking have a minimal
(0-20%) time overhead and minimal or reasonable memory overhead depends
from the language (its UTF-8 encoding and affixation).
Conversion of aspell dictionaries
Aspell dictionaries can be easily converted into hunspell. Conversion
steps:
dictionary (xx.cwl -> xx.wl):
preunzip xx.cwl
wc -l < xx.wl > xx.dic
cat xx.wl >> xx.dic
affix file
If the affix file exists, copy it:
cp xx_affix.dat xx.aff
If not, create it with the suitable character encoding (see xx.dat)
echo "SET ISO8859-x" > xx.aff
or
echo "SET UTF-8" > xx.aff
It's useful to add a TRY option with the characters of the dictionary
with frequency order to set edit distance suggestions:
echo "TRY qwertzuiopasdfghjklyxcvbnmQWERTZUIOPASDFGHJKLYXCVBNM" >>xx.aff
Conversion of aspell dictionaries
Aspell dictionaries can be easily converted into hunspell. Conversion
steps:
dictionary (xx.cwl -> xx.wl):
preunzip xx.cwl
wc -l < xx.wl > xx.dic
cat xx.wl >> xx.dic
affix file
If the affix file exists, copy it:
cp xx_affix.dat xx.aff
If not, create it with the suitable character encoding (see xx.dat)
echo "SET ISO8859-x" > xx.aff
or
echo "SET UTF-8" > xx.aff
It's useful to add a TRY option with the characters of the dictionary
with frequency order to set edit distance suggestions:
echo "TRY qwertzuiopasdfghjklyxcvbnmQWERTZUIOPASDFGHJKLYXCVBNM" >>xx.aff
SEE ALSO
hunspell (1), ispell (1), ispell (4)
2017-09-20 hunspell(5)
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