Editing Japanese grammar (section)

==Word classification==
In linguistics generally, words and affixes are often classified into two major word categories: [[lexical word|'''lexical''' words]], those that refer to the world outside of a discourse, and [[function word|'''function''' words]]—also including fragments of words—which help to build the sentence in accordance with the grammar rules of the language. Lexical words include nouns, verbs, adjectives, adverbs, and sometimes prepositions and postpositions, while grammatical words or word parts include everything else. The native tradition in Japanese grammar scholarship seems to concur in this view of classification. This native Japanese tradition uses the terminology {{Nihongo3|independent words|自立語|jiritsugo}}, for words having lexical meaning, and {{Nihongo3|auxiliary words|付属語|fuzokugo}}, for words having a grammatical function.

Classical Japanese had some auxiliary verbs (i.e., they were independent words) which have become grammaticized in modern Japanese as inflectional suffixes, such as the past tense suffix {{transliteration|ja|-ta}} (which might have developed as a contraction of {{transliteration|ja|-te ari}}).

Traditional scholarship proposes a system of word classes differing somewhat from the above-mentioned.{{Citation needed|date=March 2009}} The "independent" words have the following categories.
: {{Nihongo3||活用語|katsuyōgo}}, word classes which have inflections
:: {{Nihongo3||動詞|dōshi}}, verbs
:: {{Nihongo3||形容詞|keiyōshi}}, {{transliteration|ja|i}}-type adjectives
:: {{Nihongo3||形容動詞|keiyōdōshi}}, {{transliteration|ja|na}}-type adjectives
: {{Nihongo3||非活用語|hikatsuyōgo}} or {{Nihongo3||無活用語|mukatsuyōgo}}, word classes which do not have inflections{{Citation needed|date=March 2009}}
:: {{Nihongo3||名詞|meishi}}, nouns
:: {{Nihongo3||代名詞|daimeishi}}, pronouns
:: {{Nihongo3||副詞|fukushi}}, adverbs
:: {{Nihongo3||接続詞|setsuzokushi}}, conjunctions
:: {{Nihongo3||感動詞|kandōshi}}, interjections
:: {{Nihongo3||連体詞|rentaishi}}, prenominals

Ancillary words also divide into a nonconjugable class, containing {{nihongo|grammatical particles|助詞|joshi}} and {{nihongo|[[Japanese counter word|counter words]]|助数詞|josūshi}}, and a conjugable class consisting of {{nihongo|auxiliary verbs|助動詞|jodōshi}}. There is not wide agreement among linguists as to the English translations of the above terms.

=== Controversy over the characterization of adjectival nouns ===
Uehara (1998)<ref name="Uehara1998" />{{rp|at=chapter 2, especially §2.2.2.2}} observes that Japanese grammarians have disagreed as to the criteria that make some words inflectional and others not, in particular, the adjectival nouns – {{nihongo||形容動詞|keiyōdōshi}} or {{transliteration|ja|na}}-adjectives. (It is not disputed that nouns like {{transliteration|ja|hon}} 'book' are non-inflectional and that verbs and {{transliteration|ja|i}}-adjectives are inflectional.) The claim that adjectival nouns are inflectional rests on the claim that the element {{transliteration|ja|da}}, regarded as a copula by proponents of non-inflectional adjectival nouns, is really a suffix—an inflection. That is, {{nihongo3|'it is pretty'||kireida}} is a one-word sentence, not a two-word sentence, {{transliteration|ja|kirei da}}. However, numerous constructions show that {{transliteration|ja|da}} is less bound to the roots of nouns and adjectival nouns than {{transliteration|ja|-i}} and {{transliteration|ja|-(r)u}} are to the roots of {{transliteration|ja|i}}-adjectives and verbs, respectively.

:(1) Reduplication for emphasis
::{{nihongo3|'See! It {{em|is}} a book!'||Hora! Hon, hon!}}
::{{nihongo3|'See! It {{em|is}} pretty!'||Hora! Kirei, kirei!}}
::{{nihongo3|'See! It {{em|is}} old!'||Hora! Furu-i, furu-i!}} (the adjectival inflection {{transliteration|ja|-i}} cannot be left off)
::{{nihongo3|'See! It {{em|does}} go!'||Hora! Ik-u, ik-u!}} (the verbal inflection {{transliteration|ja|-u}} cannot be left off)
:(2) Questions. In Japanese, questions are formed by adding the particle {{transliteration|ja|ka}} (or in colloquial speech, just by changing the [[Intonation (linguistics)|intonation]] of the sentence).<ref>{{Cite web |last=平山 |first=仁美 |title=Rising Declaratives in Japanese |url=https://researchmap.jp/h_hirayama/published_papers/41250203 |archive-url=https://web.archive.org/web/20231108202903/https://web.stanford.edu/group/cslipublications/cslipublications/site/JKONLINE/29/CH12.pdf |archive-date=2023-11-08 |access-date=2023-11-08 |website=researchmap.jp}}</ref>
::{{nihongo3|'Is it a book?'||Hon ka?}}
::{{nihongo3|'Is it pretty?'||Kirei ka?}}
::{{nihongo3|'Is it old?||Furu-i ka?}} ({{transliteration|ja|-i}} cannot be left off)
::{{nihongo3|'Does it go?'||Ik-u ka?}} ({{transliteration|ja|-u}} cannot be left off)
:(3) Several epistemic modality predicates, e.g., {{nihongo3|'seem like'||mitai}}
::{{nihongo3|'It seems to be a book'||Hon mitai da}}
::{{nihongo3|'It seems to be pretty'||Kirei mitai da}}
::{{nihongo3|'It seems to be old'||Furu-i mitai da}} ({{transliteration|ja|-i}} cannot be left off)
::{{nihongo3|'It seems to go'||Ik-u mitai da}} ({{transliteration|ja|-u}} cannot be left off)

On the basis of such constructions, Uehara finds that the copula {{transliteration|ja|da}} is not suffixal and that adjectival nouns pattern with nouns in being non-inflectional.

Similarly, [[Eleanor Jorden]] considers this class of words a kind of nominal, not adjective, and refers to them as {{transliteration|ja|na}}-nominals in her textbook ''[[Japanese: The Spoken Language]]''.