What are all possible pos tags of NLTK?
To save some folks some time, here is a list I extracted from a small corpus. I do not know if it is complete, but it should have most (if not all) of the help definitions from upenn_tagset...
CC: conjunction, coordinating
& 'n and both but either et for less minus neither nor or plus sotherefore times v. versus vs. whether yetCD: numeral, cardinal
mid-1890 nine-thirty forty-two one-tenth ten million 0.5 one forty-seven 1987 twenty '79 zero two 78-degrees eighty-four IX '60s .025fifteen 271,124 dozen quintillion DM2,000 ...DT: determiner
all an another any both del each either every half la many much naryneither no some such that the them these this thoseEX: existential there
thereIN: preposition or conjunction, subordinating
astride among upon whether out inside pro despite on by throughoutbelow within for towards near behind atop around if like until belownext into if beside ...JJ: adjective or numeral, ordinal
third ill-mannered pre-war regrettable oiled calamitous first separableectoplasmic battery-powered participatory fourth still-to-be-namedmultilingual multi-disciplinary ...JJR: adjective, comparative
bleaker braver breezier briefer brighter brisker broader bumper busiercalmer cheaper choosier cleaner clearer closer colder commoner costliercozier creamier crunchier cuter ...JJS: adjective, superlative
calmest cheapest choicest classiest cleanest clearest closest commonestcorniest costliest crassest creepiest crudest cutest darkest deadliestdearest deepest densest dinkiest ...LS: list item marker
A A. B B. C C. D E F First G H I J K One SP-44001 SP-44002 SP-44005SP-44007 Second Third Three Two * a b c d first five four one six threetwoMD: modal auxiliary
can cannot could couldn't dare may might must need ought shall shouldshouldn't will wouldNN: noun, common, singular or mass
common-carrier cabbage knuckle-duster Casino afghan shed thermostatinvestment slide humour falloff slick wind hyena override subhumanitymachinist ...NNP: noun, proper, singular
Motown Venneboerger Czestochwa Ranzer Conchita Trumplane ChristosOceanside Escobar Kreisler Sawyer Cougar Yvette Ervin ODI Darryl CTCAShannon A.K.C. Meltex Liverpool ...NNS: noun, common, plural
undergraduates scotches bric-a-brac products bodyguards facets coastsdivestitures storehouses designs clubs fragrances averagessubjectivists apprehensions muses factory-jobs ...PDT: pre-determiner
all both half many quite such sure thisPOS: genitive marker
' 'sPRP: pronoun, personal
hers herself him himself hisself it itself me myself one oneself oursourselves ownself self she thee theirs them themselves they thou thy usPRP$: pronoun, possessive
her his mine my our ours their thy yourRB: adverb
occasionally unabatingly maddeningly adventurously professedlystirringly prominently technologically magisterially predominatelyswiftly fiscally pitilessly ...RBR: adverb, comparative
further gloomier grander graver greater grimmer harder harsherhealthier heavier higher however larger later leaner lengthier less-perfectly lesser lonelier longer louder lower more ...RBS: adverb, superlative
best biggest bluntest earliest farthest first furthest hardestheartiest highest largest least less most nearest second tightest worstRP: particle
aboard about across along apart around aside at away back before behindby crop down ever fast for forth from go high i.e. in into just laterlow more off on open out over per pie raising start teeth that throughunder unto up up-pp upon whole with youTO: "to" as preposition or infinitive marker
toUH: interjection
Goodbye Goody Gosh Wow Jeepers Jee-sus Hubba Hey Kee-reist Oops amenhuh howdy uh dammit whammo shucks heck anyways whodunnit honey gollyman baby diddle hush sonuvabitch ...VB: verb, base form
ask assemble assess assign assume atone attention avoid bake balkanizebank begin behold believe bend benefit bevel beware bless boil bombboost brace break bring broil brush build ...VBD: verb, past tense
dipped pleaded swiped regummed soaked tidied convened halted registeredcushioned exacted snubbed strode aimed adopted belied figgeredspeculated wore appreciated contemplated ...VBG: verb, present participle or gerund
telegraphing stirring focusing angering judging stalling lactatinghankerin' alleging veering capping approaching traveling besiegingencrypting interrupting erasing wincing ...VBN: verb, past participle
multihulled dilapidated aerosolized chaired languished panelized usedexperimented flourished imitated reunifed factored condensed shearedunsettled primed dubbed desired ...VBP: verb, present tense, not 3rd person singular
predominate wrap resort sue twist spill cure lengthen brush terminateappear tend stray glisten obtain comprise detest tease attractemphasize mold postpone sever return wag ...VBZ: verb, present tense, 3rd person singular
bases reconstructs marks mixes displeases seals carps weaves snatchesslumps stretches authorizes smolders pictures emerges stockpilesseduces fizzes uses bolsters slaps speaks pleads ...WDT: WH-determiner
that what whatever which whicheverWP: WH-pronoun
that what whatever whatsoever which who whom whosoeverWRB: Wh-adverb
how however whence whenever where whereby whereever wherein whereof why
The tag set depends on the corpus that was used to train the tagger. The default tagger of nltk.pos_tag() uses the Penn Treebank Tag Set.
In NLTK 2, you could check which tagger is the default tagger as follows:
import nltknltk.tag._POS_TAGGER>>> 'taggers/maxent_treebank_pos_tagger/english.pickle'That means that it's a Maximum Entropy tagger trained on the Treebank corpus.
nltk.tag._POS_TAGGER does not exist anymore in NLTK 3 but the documentation states that the off-the-shelf tagger still uses the Penn Treebank tagset.