In traditional grammar
, a part of speech or part-of-speech (abbreviated
as POS or PoS) is a category of words (or, more generally, of lexical item
s) that have similar grammatical
properties. Words that are assigned to the same part of speech generally display similar syntactic
behavior—they play similar roles within the grammatical structure of sentences—and sometimes similar morphology
in that they undergo inflection
for similar properties.
Commonly listed English
parts of speech are noun
, or determiner
. Other Indo-European languages
also have essentially all these word classes; one exception to this generalization is that Latin
and most Slavic languages
do not have articles. Beyond the Indo-European family, such other European languages as Hungarian
, both of which belong to the Uralic family
, completely lack prepositions or have only very few of them; rather, they have postposition
Other terms than ''part of speech''—particularly in modern linguistic
classifications, which often make more precise distinctions than the traditional scheme does—include word class, lexical class, and lexical category. Some authors restrict the term ''lexical category'' to refer only to a particular type of syntactic category
; for them the term excludes those parts of speech that are considered to be functional
, such as pronouns. The term form class is also used, although this has various conflicting definitions. Word classes may be classified as open or closed
: ''open classes'' (like nouns, verbs and adjectives) acquire new members constantly, while ''closed classes'' (such as pronouns and conjunctions) acquire new members infrequently, if at all.
Almost all languages have the word classes noun and verb, but beyond these two there are significant variations among different languages.
has as many as three classes of adjective
s, where English
have a class of nominal classifier
* Many languages do not distinguish between adjectives and adverbs, or between adjectives and verbs (see stative verb
Because of such variation in the number of categories and their identifying properties, analysis of parts of speech must be done for each individual language. Nevertheless, the labels for each category are assigned on the basis of universal criteria.
The classification of words into lexical categories is found from the earliest moments in the history of linguistics
In the ''Nirukta
'', written in the 5th or 6th century BCE, the Sanskrit
defined four main categories of words:
# नाम ''nāma'' – noun
# आख्यात ''ākhyāta'' – verb
# उपसर्ग ''upasarga'' – pre-verb or prefix
# निपात ''nipāta'' – particle
, invariant word (perhaps preposition
These four were grouped into two larger classes: inflectable
(nouns and verbs) and uninflectable (pre-verbs and particles).
The ancient work on the grammar of the Tamil language
'', argued to have been written around 2,500 years ago, classifies Tamil words as ''peyar'' (பெயர்; noun), ''vinai'' (வினை; verb), ''idai'' (part of speech which modifies the relationships between verbs and nouns), and ''uri'' (word that further qualifies a noun or verb).
A century or two after the work of Yāska, the Greek
wrote in his ''Cratylus'' dialog
, "sentences are, I conceive, a combination of verbs 'rhêma''
and nouns 'ónoma''
added another class, "conjunction" 'sýndesmos''
which included not only the words known today as conjunctions
, but also other parts (the interpretations differ; in one interpretation it is pronoun
s, and the article
By the end of the 2nd century BCE, grammarians had expanded this classification scheme into eight categories, seen in the ''Art of Grammar
'', attributed to Dionysius Thrax
(''ónoma''): a part of speech inflected for case
, signifying a concrete or abstract entity
(''rhêma''): a part of speech without case inflection, but inflected for tense
, signifying an activity or process performed or undergone
(''metokhḗ''): a part of speech sharing features of the verb and the noun
(''árthron''): a declinable part of speech, taken to include the definite article, but also the basic relative pronoun
(''antōnymíā''): a part of speech substitutable for a noun and marked for a person
(''próthesis''): a part of speech placed before other words in composition and in syntax
(''epírrhēma''): a part of speech without inflection, in modification of or in addition to a verb, adjective, clause, sentence, or other adverb
(''sýndesmos''): a part of speech binding together the discourse and filling gaps in its interpretation
It can be seen that these parts of speech are defined by morphological
500 CE) modified the above eightfold system, excluding "article" (since the Latin language
, unlike Greek, does not have articles) but adding "interjection
The Latin names for the parts of speech, from which the corresponding modern English terms derive, were ''nomen'', ''verbum'', ''participium'', ''pronomen'', ''praepositio'', ''adverbium'', ''conjunctio'' and ''interjectio''. The category ''nomen'' included substantive
s (''nomen substantivum'', corresponding to what are today called nouns in English), adjective
s ''(nomen adjectivum)'' and numeral
s ''(nomen numerale)''. This is reflected in the older English terminology ''noun substantive'', ''noun adjective'' and ''noun numeral''. Later the adjective became a separate class, as often did the numerals, and the English word ''noun'' came to be applied to substantives only.
Works of English grammar
generally follow the pattern of the European tradition as described above, except that participles are now usually regarded as forms of verbs rather than as a separate part of speech, and numerals are often conflated with other parts of speech: nouns (cardinal numeral
s, e.g., "one", and collective numeral
s, e.g., "dozen"), adjectives (ordinal numeral
s, e.g., "first", and multiplier numeral
s, e.g., "single") and adverbs (multiplicative numerals
, e.g., "once", and distributive numeral
s, e.g., "singly"). Eight or nine parts of speech are commonly listed:
or (more recently) determiner
Some modern classifications define further classes in addition to these. For discussion see the sections below.
The classification below, or slight expansions of it, is still followed in most dictionaries
;Noun (names): a word or lexical item denoting any abstract (abstract noun: e.g. ''home'') or concrete entity (concrete noun: e.g. ''house''); a person (''police officer'', ''Michael''), place (''coastline'', ''London''), thing (''necktie'', ''television''), idea (''happiness''), or quality (''bravery''). Nouns can also be classified as count noun
s or non-count nouns
; some can belong to either category. The most common part of speech; they are called naming words.
;Pronoun (replaces or places again): a substitute for a noun or noun phrase (''them, he''). Pronouns make sentences shorter and clearer since they replace nouns.
;Adjective (describes, limits): a modifier of a noun or pronoun (''big, brave''). Adjectives make the meaning of another word (noun) more precise.
;Verb (states action or being): a word denoting an action (''walk''), occurrence (''happen''), or state of being (''be''). Without a verb a group of words cannot be a clause or sentence.
;Adverb (describes, limits): a modifier of an adjective, verb, or another adverb (''very, quite''). Adverbs make language more precise.
;Preposition (relates): a word that relates words to each other in a phrase or sentence and aids in syntactic context (''in, of''). Prepositions show the relationship between a noun or a pronoun with another word in the sentence.
;Conjunction (connects): a syntactic connector; links words, phrases, or clauses (''and, but''). Conjunctions connect words or group of words
;Interjection (expresses feelings and emotions): an emotional greeting or exclamation (''Huzzah, Alas''). Interjections express strong feelings and emotions.
;Article (describes, limits):a grammatical marker of definiteness (''the'') or indefiniteness (''a, an''). The article is not always listed among the parts of speech. It is considered by some grammarians to be a type of adjective or sometimes the term 'determiner
' (a broader class) is used.
English words are not generally marked
as belonging to one part of speech or another; this contrasts with many other European languages, which use inflection
more extensively, meaning that a given word form can often be identified as belonging to a particular part of speech and having certain additional grammatical properties
. In English, most words are uninflected, while the inflected endings that exist are mostly ambiguous: ''-ed
'' may mark a verbal past tense, a participle or a fully adjectival form; ''-s
'' may mark a plural noun, a possessive noun, or a present-tense verb form; ''-ing
'' may mark a participle, gerund
, or pure adjective or noun. Although ''-ly
'' is a frequent adverb marker, some adverbs (e.g. ''tomorrow'', ''fast'', ''very'') do not have that ending, while many adjectives do have it (e.g. ''friendly'', ''ugly'', ''lovely''), as do occasional words in other parts of speech (e.g. ''jelly'', ''fly'', ''rely'').
Many English words can belong to more than one part of speech. Words like ''neigh'', ''break'', ''outlaw'', ''laser'', ''microwave'', and ''telephone'' might all be either verbs or nouns. In certain circumstances, even words with primarily grammatical functions can be used as verbs or nouns, as in, "We must look to the ''hows'' and not just the ''whys''." The process whereby a word comes to be used as a different part of speech is called conversion
or zero derivation.
recognize that the above list of eight or nine word classes is drastically simplified. For example, "adverb" is to some extent a catch-all class that includes words with many different functions. Some have even argued that the most basic of category distinctions, that of nouns and verbs, is unfounded, or not applicable to certain languages. Modern linguists have proposed many different schemes whereby the words of English or other languages are placed into more specific categories and subcategories based on a more precise understanding of their grammatical functions.
Common lexical category set defined by function may include the following (not all of them will necessarily be applicable in a given language):
* Categories that will usually be open classes
s (except auxiliary verbs)
* Categories that will usually be closed classes:
** auxiliary verb
s, demonstrative adjective
s, and possessive adjective
** measure word
s or classifier
s (prepositions, postpositions, and circumpositions)
** cardinal number
Within a given category, subgroups of words may be identified based on more precise grammatical properties. For example, verbs may be specified according to the number and type of object
s or other complement
s which they take. This is called subcategorization
Many modern descriptions of grammar include not only lexical categories or word classes, but also ''phrasal categories'', used to classify phrase
s, in the sense of groups of words that form units having specific grammatical functions. Phrasal categories may include noun phrase
s (NP), verb phrase
s (VP) and so on. Lexical and phrasal categories together are called syntactic categories
Open and closed classes
Word classes may be either open or closed. An open class is one that commonly accepts the addition of new words, while a closed class is one to which new items are very rarely added. Open classes normally contain large numbers of words, while closed classes are much smaller. Typical open classes found in English and many other languages are noun
s (excluding auxiliary verbs
, if these are regarded as a separate class), adjective
s and interjection
s are often an open class, though less familiar to English speakers,
[''The Art of Grammar: A Practical Guide,'' Alexandra Y. Aikhenvald]
/ref> and are often open to nonce words. Typical closed classes are prepositions (or postpositions), determiners, conjunctions, and pronouns.
The open–closed distinction is related to the distinction between lexical and functional categories, and to that between content words and function words, and some authors consider these identical, but the connection is not strict. Open classes are generally lexical categories in the stricter sense, containing words with greater semantic content,
while closed classes are normally functional categories, consisting of words that perform essentially grammatical functions. This is not universal: in many languages verbs and adjectives [''Adjective classes: a cross-linguistic typology,'' Robert M. W. Dixon, Alexandra Y. Aikhenvald, OUP Oxford, 2006] [''The Art of Grammar: A Practical Guide,'' Alexandra Y. Aikhenvald]
/ref> are closed classes, usually consisting of few members, and in Japanese the formation of new pronouns from existing nouns is relatively common, though to what extent these form a distinct word class is debated.
Words are added to open classes through such processes as compounding, derivation, coining, and borrowing. When a new word is added through some such process, it can subsequently be used grammatically in sentences in the same ways as other words in its class. A closed class may obtain new items through these same processes, but such changes are much rarer and take much more time. A closed class is normally seen as part of the core language and is not expected to change. In English, for example, new nouns, verbs, etc. are being added to the language constantly (including by the common process of verbing and other types of conversion, where an existing word comes to be used in a different part of speech). However, it is very unusual for a new pronoun, for example, to become accepted in the language, even in cases where there may be felt to be a need for one, as in the case of gender-neutral pronouns.
The open or closed status of word classes varies between languages, even assuming that corresponding word classes exist. Most conspicuously, in many languages verbs and adjectives form closed classes of content words. An extreme example is found in Jingulu, which has only three verbs, while even the modern Indo-European Persian has no more than a few hundred simple verbs, a great deal of which are archaic. (Some twenty Persian verbs are used as light verbs to form compounds; this lack of lexical verbs is shared with other Iranian languages.) Japanese is similar, having few lexical verbs. Basque verbs are also a closed class, with the vast majority of verbal senses instead expressed periphrastically.
In Japanese, verbs and adjectives are closed classes, though these are quite large, with about 700 adjectives,
[''The Art of Grammar: A Practical Guide,'' Alexandra Y. Aikhenvald]
/ref> and verbs have opened slightly in recent years. Japanese adjectives are closely related to verbs (they can predicate a sentence, for instance). New verbal meanings are nearly always expressed periphrastically by appending to a noun, as in , and new adjectival meanings are nearly always expressed by adjectival nouns, using the suffix when an adjectival noun modifies a noun phrase, as in . The closedness of verbs has weakened in recent years, and in a few cases new verbs are created by appending to a noun or using it to replace the end of a word. This is mostly in casual speech for borrowed words, with the most well-established example being , from .
This recent innovation aside, the huge contribution of Sino-Japanese vocabulary was almost entirely borrowed as nouns (often verbal nouns or adjectival nouns). Other languages where adjectives are closed class include Swahili, Bemba, and Luganda.
By contrast, Japanese pronouns are an open class and nouns become used as pronouns with some frequency; a recent example , now used by some young men as a first-person pronoun. The status of Japanese pronouns as a distinct class is disputed, however, with some considering it only a use of nouns, not a distinct class. The case is similar in languages of Southeast Asia, including Thai and Lao, in which, like Japanese, pronouns and terms of address vary significantly based on relative social standing and respect. [''The Art of Grammar: A Practical Guide,'' Alexandra Y. Aikhenvald]
Some word classes are universally closed, however, including demonstratives and interrogative words.
* Part-of-speech tagging
* Sliding window based part-of-speech tagging
The parts of speech
Guide to Grammar and Writing
Martin Haspelmath. 2001. "Word Classes and Parts of Speech." In: Baltes, Paul B. & Smelser, Neil J. (eds.) ''International Encyclopedia of the Social and Behavioral Sciences''. Amsterdam: Pergamon, 16538–16545.