Tokenization in Korean, plus abjad languages (#38)

* Remove marks from more languages

* Add Korean tokenization, and include MeCab files in data

* add a Hebrew tokenization test

* fix terminology in docstrings about abjad scripts

* combine Japanese and Korean tokenization into the same function


Former-commit-id: fec6eddcc3
This commit is contained in:
Rob Speer 2016-07-15 15:10:25 -04:00 committed by Lance Nathan
parent ac24b8eab4
commit a0893af82e
24 changed files with 7058 additions and 62 deletions

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@ -1,3 +1,8 @@
recursive-include wordfreq/data *.gz
include README.md
recursive-include wordfreq/data *.txt
recursive-include wordfreq/data *.bin
recursive-include wordfreq/data *.def
recursive-include wordfreq/data *.dic
recursive-include wordfreq/data dicrc
recursive-include wordfreq/data COPYING

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@ -276,7 +276,11 @@ The terms of use of this data are:
acknowledgement of Google Books Ngram Viewer as the source, and inclusion
of a link to http://books.google.com/ngrams, would be appreciated.
It also contains data derived from the following Creative Commons-licensed
`wordfreq` uses MeCab, by Taku Kudo, plus Korean data files by Yongwoon Lee and
Yungho Yu. The Korean data is under an Apache 2 license, a copy of which
appears in wordfreq/data/mecab-ko-dic/COPYING.
`wordfreq` also contains data derived from the following Creative Commons-licensed
sources:
- The Leeds Internet Corpus, from the University of Leeds Centre for Translation

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@ -34,7 +34,7 @@ if sys.version_info < (3, 4):
setup(
name="wordfreq",
version='1.4.1',
version='1.4.2',
maintainer='Luminoso Technologies, Inc.',
maintainer_email='info@luminoso.com',
url='http://github.com/LuminosoInsight/wordfreq/',
@ -47,10 +47,10 @@ setup(
include_package_data=True,
install_requires=dependencies,
# mecab-python3 is required for looking up Japanese word frequencies. In
# turn, it depends on libmecab-dev being installed on the system. It's not
# listed under 'install_requires' because wordfreq should be usable in
# other languages without it.
# mecab-python3 is required for looking up Japanese or Korean word
# frequencies. In turn, it depends on libmecab-dev being installed on the
# system. It's not listed under 'install_requires' because wordfreq should
# be usable in other languages without it.
#
# Similarly, jieba is required for Chinese word frequencies.
extras_require={

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@ -152,7 +152,7 @@ def test_not_enough_ascii():
random_ascii_words(lang='zh')
def test_ar():
def test_arabic():
# Remove tatweels
eq_(
tokenize('متــــــــعب', 'ar'),
@ -183,6 +183,7 @@ def test_ideographic_fallback():
['ひらがな', 'カタカナ', 'romaji']
)
def test_other_languages():
# Test that we leave Thai letters stuck together. If we had better Thai support,
# we would actually split this into a three-word phrase.
eq_(tokenize('การเล่นดนตรี', 'th'), ['การเล่นดนตรี'])
@ -194,3 +195,7 @@ def test_ideographic_fallback():
# Test Hindi -- tokens split where there are spaces, and not where there aren't
eq_(tokenize('हिन्दी विक्षनरी', 'hi'), ['हिन्दी', 'विक्षनरी'])
# Remove vowel points in Hebrew
eq_(tokenize('דֻּגְמָה', 'he'), ['דגמה'])

22
tests/test_korean.py Normal file
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@ -0,0 +1,22 @@
from nose.tools import eq_, assert_almost_equal
from wordfreq import tokenize, word_frequency
def test_tokens():
eq_(tokenize('감사합니다', 'ko'),
['감사', '합니다'])
def test_combination():
gamsa_freq = word_frequency('감사', 'ko')
habnida_freq = word_frequency('합니다', 'ko')
assert_almost_equal(
word_frequency('감사감사', 'ko'),
gamsa_freq / 2
)
assert_almost_equal(
1.0 / word_frequency('감사합니다', 'ko'),
1.0 / gamsa_freq + 1.0 / habnida_freq
)

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@ -0,0 +1,29 @@
;
; Configuration file of IPADIC
;
; $Id: dicrc,v 1.4 2006/04/08 06:41:36 taku-ku Exp $;
;
cost-factor = 800
bos-feature = BOS/EOS,*,*,*,*,*,*,*,*
eval-size = 8
unk-eval-size = 4
config-charset = UTF-8
; yomi
node-format-yomi = %pS%f[7]
unk-format-yomi = %M
eos-format-yomi = \n
; simple
node-format-simple = %m\t%F-[0,1,2,3]\n
eos-format-simple = EOS\n
; ChaSen
node-format-chasen = %m\t%f[7]\t%f[6]\t%F-[0,1,2,3]\t%f[4]\t%f[5]\n
unk-format-chasen = %m\t%m\t%m\t%F-[0,1,2,3]\t\t\n
eos-format-chasen = EOS\n
; ChaSen (include spaces)
node-format-chasen2 = %M\t%f[7]\t%f[6]\t%F-[0,1,2,3]\t%f[4]\t%f[5]\n
unk-format-chasen2 = %M\t%m\t%m\t%F-[0,1,2,3]\t\t\n
eos-format-chasen2 = EOS\n

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@ -0,0 +1 @@
c926154d533ccaef1515af6883056d69c34ca239

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@ -0,0 +1,201 @@
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@ -0,0 +1,25 @@
;
; Configuration file of mecab-ko-dic
;
# 비용 값으로 변환할 때 배율 팩터입니다. 700에서 800에서 문제가 없습니다.
cost-factor = 800
# 문장의 시작, 문장 끝에 대한 소성(素性)입니다. CSV로 표현합니다.
bos-feature = BOS/EOS,*,*,*,*,*,*,*,*
# 알려진 단어의 경우 소성(素性)의 처음부터 몇 개까지 일치하면 정답으로
# 인정하는지를 지정합니다. 일반적으로 알려진 단어는 품사 활용 등의 정보만
# 맞추면 되기 때문에, "읽기", "발음" 소성(素性)은 무시하도록 합니다.
# 여기에서는 3가지가 평가됩니다.
eval-size = 4
# 알 수 없는 단어의 경우
# 소성의 처음부터 몇 개까지 일치하면 정답으로 인정할지를 지정합니다.
unk-eval-size = 2
# dicrc, char.def, unk.def, pos-id.def 파일의 문자 코드셋입니다.
config-charset = UTF-8
# 좌측에 공백을 포함하는 품사의 연접 비용을 늘리기 위한 설정입니다.
# mecab-ko에서만 사용되는 설정입니다. 다음과 같은 형식을 가집니다.
# <posid 1>,<posid 1 penalty cost>,<posid 2>,<posid 2 penalty cost>...
#
# 예) 120,6000 => posid가 120인 품사(조사)의 좌측에 공백을 포함할 경우
# 연접 비용을 6000만큼 늘림
left-space-penalty-factor = 100,3000,120,6000,172,3000,183,3000,184,3000,185,3000,200,3000,210,6000,220,3000,221,3000,222,3000,230,3000

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2dbb57fe707d7dddd2392526aad7cbac77378bb3

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58619494b4f81190218b76d9d2090607830e51ec

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@ -0,0 +1,66 @@
UNKNOWN,*,*,*,*,*,*,*,* 0
*,*,*,*,Compound,*,*,*,* 1
*,*,*,*,Inflect,EC,*,*,* 200
*,*,*,*,Inflect,EF,*,*,* 200
*,*,*,*,Inflect,EP,*,*,* 200
*,*,*,*,Inflect,ETM,*,*,* 200
*,*,*,*,Inflect,ETN,*,*,* 200
*,*,*,*,Inflect,JC,*,*,* 210
*,*,*,*,Inflect,JKB,*,*,* 210
*,*,*,*,Inflect,JKC,*,*,* 210
*,*,*,*,Inflect,JKG,*,*,* 210
*,*,*,*,Inflect,JKO,*,*,* 210
*,*,*,*,Inflect,JKQ,*,*,* 210
*,*,*,*,Inflect,JKS,*,*,* 210
*,*,*,*,Inflect,JKV,*,*,* 210
*,*,*,*,Inflect,JX,*,*,* 210
*,*,*,*,Inflect,XSA,*,*,* 220
*,*,*,*,Inflect,XSN,*,*,* 221
*,*,*,*,Inflect,XSV,*,*,* 222
*,*,*,*,Inflect,VCP,*,*,* 230
*,*,*,*,Inflect,*,*,*,* 2
*,*,*,*,Preanalysis,*,*,*,* 3
EC,*,*,*,*,*,*,*,* 100
EF,*,*,*,*,*,*,*,* 100
EP,*,*,*,*,*,*,*,* 100
ETM,*,*,*,*,*,*,*,* 100
ETN,*,*,*,*,*,*,*,* 100
IC,*,*,*,*,*,*,*,* 110
JC,*,*,*,*,*,*,*,* 120
JKB,*,*,*,*,*,*,*,* 120
JKC,*,*,*,*,*,*,*,* 120
JKG,*,*,*,*,*,*,*,* 120
JKO,*,*,*,*,*,*,*,* 120
JKQ,*,*,*,*,*,*,*,* 120
JKS,*,*,*,*,*,*,*,* 120
JKV,*,*,*,*,*,*,*,* 120
JX,*,*,*,*,*,*,*,* 120
MAG,*,*,*,*,*,*,*,* 130
MAJ,*,*,*,*,*,*,*,* 131
MM,*,*,*,*,*,*,*,* 140
NNG,*,*,*,*,*,*,*,* 150
NNP,*,*,*,*,*,*,*,* 150
NNB,*,*,*,*,*,*,*,* 150
NNBC,*,*,*,*,*,*,*,* 150
NP,*,*,*,*,*,*,*,* 150
NR,*,*,*,*,*,*,*,* 150
SF,*,*,*,*,*,*,*,* 160
SH,*,*,*,*,*,*,*,* 161
SL,*,*,*,*,*,*,*,* 162
SN,*,*,*,*,*,*,*,* 163
SP,*,*,*,*,*,*,*,* 164
SSC,*,*,*,*,*,*,*,* 165
SSO,*,*,*,*,*,*,*,* 166
SC,*,*,*,*,*,*,*,* 167
SY,*,*,*,*,*,*,*,* 168
SE,*,*,*,*,*,*,*,* 169
VA,*,*,*,*,*,*,*,* 170
VCN,*,*,*,*,*,*,*,* 171
VCP,*,*,*,*,*,*,*,* 172
VV,*,*,*,*,*,*,*,* 173
VX,*,*,*,*,*,*,*,* 174
XPN,*,*,*,*,*,*,*,* 181
XR,*,*,*,*,*,*,*,* 182
XSA,*,*,*,*,*,*,*,* 183
XSN,*,*,*,*,*,*,*,* 184
XSV,*,*,*,*,*,*,*,* 185

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@ -0,0 +1,51 @@
# Feature(POS) to Internal State mapping
#
# () () .
#
# CRF는 unigram, bigram, bigram의 3
#
#
# .
#
# ()
#
# .
#
# * :
# (AB|CD|EF) : AB CD EF
# AB : AB에만
#
# () $1 $2, $3.. ()
# (CSV로 ) .
#
# ,,,,,,
#
# Unigram
[unigram rewrite]
*,*,*,*,*,*,*,*,* $1,$2,$3,$4,$5,$6,$7,$8,$9
# bigram
# ($2) .
# ,,($1,$2,*,$4) .
# /NNG,T,*,*,*,*,* + /J,*,,*,*,*,*
#
[left rewrite]
BOS/EOS,*,*,*,*,*,*,*,* $1,$2,$3,$4,$5,$6,$7,$8,BOS/EOS
SF,*,*,*,*,*,*,*,* $1,$2,$3,$4,$5,$6,$7,$8,BOS/EOS
*,*,*,*,Inflect,(JC|JKB|JKC|JKG|JKO|JKQ|JKS|JKV|JX|NNB|NNBC|VCP|ETM|XSN),*,*,* $6,$2,*,$4,*,*,*,*,*
*,*,*,*,(Inflect|Preanalysis),*,*,*,* $6,$2,*,*,*,*,*,*,*
(JC|JKB|JKC|JKG|JKO|JKQ|JKS|JKV|JX|NNB|NNBC|VCP|ETM|XSN),*,*,*,*,*,*,*,* $1,$2,*,$4,*,*,*,*,*
*,*,*,*,*,*,*,*,* $1,$2,*,*,*,*,*,*,*
# bigram
# ($3) .
# ,,,($1,$2,$3,$4) .
# ex) /NN,T,*,*,*,*,* + /J,T,,*,*,*,*
[right rewrite]
BOS/EOS,*,*,*,*,*,*,*,* $1,$2,$3,$4,$5,$6,$7,$8,BOS/EOS
SF,*,*,*,*,*,*,*,* $1,$2,$3,$4,$5,$6,$7,$8,BOS/EOS
SL,*,*,*,*,*,*,*,* NNG,$2,$3,*,*,*,*,*,*
*,*,*,*,Inflect,*,(JC|JKB|JKC|JKG|JKO|JKQ|JKS|JKV|JX|NNB|NNBC|XSN),*,* $7,$2,$3,$4,*,*,*,*,*
*,*,*,*,(Inflect|Preanalysis),*,*,*,* $7,$2,$3,*,*,*,*,*,*
(JC|JKB|JKC|JKG|JKO|JKQ|JKS|JKV|JX|NNB|NNBC|XSN),*,*,*,*,*,*,*,* $1,$2,$3,$4,*,*,*,*,*
*,*,*,*,*,*,*,*,* $1,$2,$3,*,*,*,*,*,*

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9655d23c3a0900764cbcdb8d8395d0f09ec098ed

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@ -1,21 +0,0 @@
import MeCab
import unicodedata
# Instantiate the MeCab analyzer, which the mecab-python3 interface calls a
# Tagger.
MECAB_ANALYZER = MeCab.Tagger()
def mecab_tokenize(text):
"""
Use the mecab-python3 package to tokenize the given Japanese text.
The simplest output from mecab-python3 is the single-string form, which
contains the same table that the command-line version of MeCab would output.
We find the tokens in the first column of this table.
"""
text = unicodedata.normalize('NFKC', text.strip())
return [line.split('\t')[0]
for line in MECAB_ANALYZER.parse(text).split('\n')
if line != '' and line != 'EOS']

28
wordfreq/mecab.py Normal file
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@ -0,0 +1,28 @@
from pkg_resources import resource_filename
import MeCab
import unicodedata
# Instantiate the MeCab analyzers for each language.
MECAB_ANALYZERS = {
'ja': MeCab.Tagger('-d %s' % resource_filename('wordfreq', 'data/mecab-ja-ipadic')),
'ko': MeCab.Tagger('-d %s' % resource_filename('wordfreq', 'data/mecab-ko-dic'))
}
def mecab_tokenize(text, lang):
"""
Use the mecab-python3 package to tokenize the given text. The `lang`
must be 'ja' for Japanese or 'ko' for Korean.
The simplest output from mecab-python3 is the single-string form, which
contains the same table that the command-line version of MeCab would output.
We find the tokens in the first column of this table.
"""
if lang not in MECAB_ANALYZERS:
raise ValueError("Can't run MeCab on language %r" % lang)
analyzer = MECAB_ANALYZERS[lang]
text = unicodedata.normalize('NFKC', text.strip())
return [line.split('\t')[0]
for line in analyzer.parse(text).split('\n')
if line != '' and line != 'EOS']

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@ -2,6 +2,9 @@ import regex
import unicodedata
mecab_tokenize = None
jieba_tokenize = None
# See the documentation inside TOKEN_RE for why we have to handle these
# scripts specially.
SPACELESS_SCRIPTS = [
@ -23,7 +26,6 @@ def _make_spaceless_expr():
SPACELESS_EXPR = _make_spaceless_expr()
TOKEN_RE = regex.compile(r"""
# Case 1: a special case for non-spaced languages
# -----------------------------------------------
@ -74,7 +76,7 @@ TOKEN_RE_WITH_PUNCTUATION = regex.compile(r"""
\S(?:\B\S|\p{M})*
""".replace('<SPACELESS>', SPACELESS_EXPR), regex.V1 | regex.WORD | regex.VERBOSE)
ARABIC_MARK_RE = regex.compile(r'[\p{Mn}\N{ARABIC TATWEEL}]', regex.V1)
MARK_RE = regex.compile(r'[\p{Mn}\N{ARABIC TATWEEL}]', regex.V1)
def simple_tokenize(text, include_punctuation=False):
@ -98,6 +100,13 @@ def simple_tokenize(text, include_punctuation=False):
tokens.
- It breaks on all spaces, even the "non-breaking" ones.
- It aims to keep marks together with words, so that they aren't erroneously
split off as punctuation in languages such as Hindi.
- It keeps Southeast Asian scripts, such as Thai, glued together. This yields
tokens that are much too long, but the alternative is that every character
would end up in its own token, which is worse.
"""
text = unicodedata.normalize('NFC', text)
token_expr = TOKEN_RE_WITH_PUNCTUATION if include_punctuation else TOKEN_RE
@ -114,20 +123,20 @@ def turkish_tokenize(text, include_punctuation=False):
return [token.strip("'").casefold() for token in token_expr.findall(text)]
mecab_tokenize = None
def japanese_tokenize(text, include_punctuation=False):
def tokenize_mecab_language(text, lang, include_punctuation=False):
"""
Tokenize Japanese text, initializing the MeCab tokenizer if necessary.
Tokenize Japanese or Korean text, initializing the MeCab tokenizer if necessary.
"""
global mecab_tokenize
if lang not in {'ja', 'ko'}:
raise ValueError("Only Japanese and Korean can be tokenized using MeCab")
if mecab_tokenize is None:
from wordfreq.japanese import mecab_tokenize
tokens = mecab_tokenize(text)
from wordfreq.mecab import mecab_tokenize
tokens = mecab_tokenize(text, lang)
token_expr = TOKEN_RE_WITH_PUNCTUATION if include_punctuation else TOKEN_RE
return [token.casefold() for token in tokens if token_expr.match(token)]
jieba_tokenize = None
def chinese_tokenize(text, include_punctuation=False, external_wordlist=False):
"""
Tokenize Chinese text, initializing the Jieba tokenizer if necessary.
@ -140,16 +149,16 @@ def chinese_tokenize(text, include_punctuation=False, external_wordlist=False):
return [token.casefold() for token in tokens if token_expr.match(token)]
def remove_arabic_marks(text):
def remove_marks(text):
"""
Remove decorations from Arabic words:
Remove decorations from words in abjad scripts:
- Combining marks of class Mn, which tend to represent non-essential
vowel markings.
- Tatweels, horizontal segments that are used to extend or justify a
word.
- Tatweels, horizontal segments that are used to extend or justify an
Arabic word.
"""
return ARABIC_MARK_RE.sub('', text)
return MARK_RE.sub('', text)
def tokenize(text, lang, include_punctuation=False, external_wordlist=False):
@ -158,30 +167,68 @@ def tokenize(text, lang, include_punctuation=False, external_wordlist=False):
the language. Strings that are looked up in wordfreq will be run through
this function first, so that they can be expected to match the data.
Here is what the tokenizer will do, depending on the language:
Some of the processing steps are specific to one language, such as Chinese,
but what broadly happens to the text depends on what general writing system
the language uses, out of these categories:
- Chinese will be mapped to Simplified Chinese characters and tokenized
using the Jieba tokenizer, trained on a custom word list of words that
can be looked up in wordfreq.
- Alphabetic scripts: English, Spanish, Russian, etc.
- Abjad scripts: Arabic, Hebrew, Persian, Urdu, etc.
- CJK scripts: Chinese, Japanese, Korean
- Brahmic scripts: Hindi, Tamil, Telugu, Kannada, etc.
- Japanese will be delegated to the external mecab-python module. It will
be NFKC normalized, which is stronger than NFC normalization.
- Chinese or Japanese texts that aren't identified as the appropriate
language will only split on punctuation and script boundaries, giving
you untokenized globs of characters that probably represent many words.
Alphabetic scripts
------------------
- Arabic will be NFKC normalized, and will have Arabic-specific combining
marks and tatweels removed.
The major alphabetic scripts -- Latin, Cyrillic, and Greek -- cover most
European languages, which are relatively straightforward to tokenize.
- Languages written in cased alphabets will be case-folded to lowercase.
Text in these scripts will be normalized to NFC form, then passed
through a regular expression that implements the Word Segmentation section
of Unicode Annex #29, and then case-folded to lowercase.
- Turkish will use a different case-folding procedure, so that capital
I and İ map to ı and i respectively.
The effect is mostly to split the text on spaces and punctuation. There are
some subtleties involving apostrophes inside words, which the regex will
only split when they occur before a vowel. ("Hasn't" is one token, but
"l'enfant" is two.)
- Languages besides Japanese and Chinese will be tokenized using a regex
that mostly implements the Word Segmentation section of Unicode Annex
#29. See `simple_tokenize` for details.
If the language is Turkish, the case-folding rules will take this into
account, so that capital I and İ map to ı and i respectively.
Abjad scripts
-------------
Languages in the Arabic or Hebrew scripts are written with optional vowel
marks, and sometimes other decorative markings and ligatures. In these
languages:
- The text will be NFKC-normalized, which is a stronger and lossier form
than NFC. Here its purpose is to reduce ligatures to simpler characters.
- Marks will be removed, as well as the Arabic tatweel (an extension of
a word that is used for justification or decoration).
After these steps, the text will go through the same process as the
alphabetic scripts above.
CJK scripts
-----------
In the CJK languages, word boundaries can't usually be identified by a
regular expression. Instead, there needs to be some language-specific
handling.
- Chinese text first gets converted to a canonical representation we call
"Oversimplified Chinese", where all characters are replaced by their
Simplified Chinese form, no matter what, even when this misspells a word or
a name. This representation is then tokenized using the Jieba tokenizer,
trained on the list of Chinese words that can be looked up in wordfreq.
- Japanese and Korean will be NFKC-normalized, then tokenized using the
MeCab tokenizer, using dictionary files that are included in this
package.
The `external_wordlist` option only affects Chinese tokenization. If it's
True, then wordfreq will not use its own Chinese wordlist for tokenization.
@ -189,15 +236,36 @@ def tokenize(text, lang, include_punctuation=False, external_wordlist=False):
and it will leave Traditional Chinese characters as is. This will probably
give more accurate tokenization, but the resulting tokens won't necessarily
have word frequencies that can be looked up.
If you end up seeing tokens that are entire phrases or sentences glued
together, that probably means you passed in CJK text with the wrong
language code.
Brahmic scripts and other languages
-----------------------------------
Any kind of language not previously mentioned will just go through the same
tokenizer that alphabetic languages use.
We've tweaked this tokenizer for the case of Indic languages in Brahmic
scripts, such as Hindi, Tamil, and Telugu, so that we can handle these
languages where the default Unicode algorithm wouldn't quite work.
Southeast Asian languages, such as Thai, Khmer, Lao, and Myanmar, are
written in Brahmic-derived scripts, but usually *without spaces*. wordfreq
does not support these languages yet. It will split on spaces and
punctuation, giving tokens that are far too long.
"""
if lang == 'ja':
return japanese_tokenize(text, include_punctuation)
if lang == 'ja' or lang == 'ko':
return tokenize_mecab_language(text, lang, include_punctuation)
elif lang == 'zh':
return chinese_tokenize(text, include_punctuation, external_wordlist)
elif lang == 'tr':
return turkish_tokenize(text, include_punctuation)
elif lang == 'ar':
text = remove_arabic_marks(unicodedata.normalize('NFKC', text))
elif lang in {'ar', 'bal', 'fa', 'ku', 'ps', 'sd', 'tk', 'ug', 'ur', 'he', 'yi'}:
# Abjad languages
text = remove_marks(unicodedata.normalize('NFKC', text))
return simple_tokenize(text, include_punctuation)
else:
return simple_tokenize(text, include_punctuation)