Vowels

• /a/: [a]
• /i/: [i]
• /u/: [u]
• /e/: [je]^[5][6][7]
• /o/: [wo]

Consonants

Phonetic realization

Case particle

• 「が」 (ga) and 「の」 (no) : "of, ...'s". It hints the present of subject, relation of modification between phrases or nouns.
• 「を」(wo) (accusative). Optional.
• 「に」(ni) (dative/locative). It had a wide range of functions ('to' or 'for' a person; 'by' an agent'; 'at' or 'to' a place; 'at' a time), and in some uses, especially when indicating time, it was optional.
• 「より」(yori) (ablative).
• 「まで」(made) (terminative: 'until'; 'as far as').
• 「と」(to) (comitative: 'with'; essive 'as').
• 「へ」(fe) (allative: 'to'). 「へ」 was derived from the noun「 邊(へ)」'vicinity; direction', which 「わ」 occasionally found in the location noun structure Noun + 「の」 + Location Noun to mean 'near', or in the noun-deriving suffix 「べ」 (< 「のへ」) in such words as 水(みづ)べ 'beside the water' .

The nominative function was marked by the absence of a particle in main clauses and by the genitive particles in subordinate clauses. The dative/locative particle -ni was homophonous with the simple infinitive form of the copula -ni, with verbal suffixes supplies more complex case markers -ni-te ('at' a place) and -ni si-te or -ni-te ('by means of'). A number of particle + verb + -te sequences provided other case functions: -ni yori-te 'due to' (from yor- 'depend'), -ni tuki-te 'about, concerning' (from tuk- 'be attached'), and -to si-te 'as' (from se- 'do'). More complex structures were derived from genitive particle + Location Noun + appropriate case particle (typically locative -ni) and were used particularly to express spatial and temporal relations. Major location nouns were mafe 'front' (Noun-no mafe-ni 'in front of Noun'), ufe 'top' (Noun-no ufe-ni 'on top of Noun' ~ 'above Noun'), sita 'under' (Noun-no sita-ni 'under Noun), saki 'ahead' (Noun-no saki-ni 'ahead of Noun)', etc.

Conjunctive particle

• Infinitive + 「て」(te): 'and (then/so), when, because'. It usually expressed a close sequential link between the predicates that it connects. The subjects of the two verbs connected by「て」 were usually the same.
• Realis + 「ば」(ba): 'and (then/so), when, because'. It usually expressed a looser sequential link between the predicates that it connected. The subject of both verbs connected by 「ば」 was usually different.
• Irrealis + 「ば」(ba): 'if...', It usually expressed a unreal condition.
• Irrealis + 「で」(de):^[12] negative 'and', 'without ... ing', 'rather than ... ', derived from old infinitive of negative auxiliary verb「ず」(i.e. 「に」) + the particle 「て」with sound change.
• Various forms + 「と/とも」 (do / domo): 'even if, even though'. Most yougens and auxiliary verbs took the conclusive form, bigrade verbs take the infinitive in earlier texts, r-irregular verbs took the attributive form,and some auxiliary verbs inflecting like adjective and negative auxiliary verbs「ず」also took the attributive.
• Infinitive + 「つつ」 (tutu): 'while (at the same time)'.
• Infinitive of verb / stem of adjective + 「ながら」(nagara): 'while, while still' or 'despite'.

Binding particle

There were some special particles that limited the inflectional form of the yougen or auxiliary verb at the end of a sentence. These particles are called binding particles(係(かかり)助(じょ)詞(し)). These limitations are called binding rules(係(かか)り結(むす)びの法(ほう)則(そく)).

Note that the case particle「と」indicates a preceding quote, and when it is used, a quote should be considered an independent sentence when using the linking rule.

Susumu Ōno assumed that these binding particles originally acted as final particles.^[13] For example:

Man'yōgana: 苦毛 零來雨可 (from Man'yōshū, 265th)

Modern transliteration: 苦(くる)しくも　降(ふ)り来(く)る雨(あめ)か

Notice that 「来る」 is attributive(Due to the modification to the noun 「雨」). According to Susumu Ōno's assumption, if we want to emphasize the noun in question(i.e.「雨」), we can invert the whole sentence as the following:

雨か降り来る

Obviously, this gives birth to the binding rule. Since other binding particles can also be considered final particles in Old Japanese, this assumption is reasonable.

Conjugation

Early Middle Japanese inherited all eight verbal conjugations class from Old Japanese and added new one: Lower Monograde, but there's only 「蹴(け)る」("kick by foot") classified as Lower Monograde in Early Middle Japanese.

Early Middle Japanese Verbs were divided into 5 class of regular conjugations:

Quadrigrade (四段, yodan), Upper monograde (上一段, kami ichidan), Lower monograde (下一段, shimo ichidan), Upper bigrade (上二段, kami nidan), Lower bigrade (下二段, shimo nidan).

There were also 4 "irregular" (変格) conjugations:

K-irregular (カ変, kahen), S-irregular (サ変, sahen), N-irregular (ナ変, nahen), R-irregular (ラ変, rahen).

The conjugation of each is divided into 6 Inflectional forms(活(かつ)用(よう)形(けい)):

• Irrealis (未然形, mizenkei, "imperfect form")
• Infinitive (連用形, ren'yōkei, "form linking to Yougen")
• Conclusive (終止形, shūshikei, "form to end [a sentence]")
• Attributive (連体形, rentaikei, "form linking to Taigen")
• Realis (已然形, izenkei, "perfect form")
• Imperative (命令形, meireikei,"form to give order")

The English names for the irrealis and the realis differ from author to author, including negative and evidential, or imperfective and perfective.

In following table, red part means stem, while blue part means Inflectional suffix.

• Inflectional form = (stem) + Inflectional suffix (活(かつ)用(よう)形(けい) = 語(ご)幹(かん) + 活用語(ご)尾(び))
• Inflectional suffix = root consonant + real suffix (root consonant is unique to every verb.)

*Noted that most S-irregular is the combination of a noun and 「爲(す)」, for example, 「期(き)す」 is a combination of the noun 「期(き)」 ('date') and 「爲(す)」.

The 「よ」 at the end of the imperative forms is optional, although exceedingly common.

The system of 9 conjugation classes appears to be complex. However, all nine conjugations can be subsumed into variations of two groups:

• the consonant-root verbs (quadrigrade, N-irregular and R-irregular verbs)
• the vowel-root verbs (others)

The irregularity of N-irregular verbs occurred only in the conclusive and the attributive, and as there are no quadrigrade verbs with n-roots, quadrigrade and N-irregular verb patterns may be treated as being in complementary distribution.^[14] Vowel-root verbs consist of bigrade verbs (the majority), a few monograde verbs (especially 見(み)る 'see' and 居(ゐ)る 'sit'), the K-irregular verb 来(く) 'come', and the S-irregular verb se- 'do' (or -ze- in some compounds).^[15] The difference between 'upper' and 'lower' bigrade or monograde verbs is whether the vowel at the end of the root was i or e. The difference between bigrade and monograde was whether in the conclusive, attributive, and realis, the initial u of the ending elided the vowel of the root or the vowel of the roots elides the initial u of the ending.

There are some questions about this arrangement of forms:^[16]

• The irrealis is not used as an independent verb form: it must be followed by an auxiliary.

  That said, there is a limited set of nouns appearing in Old Japanese and ending in -a, that appear to overlap phonetically and semantically with the irrealis form of certain verbs. These could be analyzed as resultative deverbal nouns.

• The classical passive auxiliary verb 「る」 (「ゆ」in Old Japanese) attaches to the irrealis stem with an -a ending (i.e. quadrigrade, N-irregular and R-irregular), while the other classical passive auxiliary 「らる」 (「らゆ」in Old Japanese) attaches to the irrealis stem without an -a ending (i.e. for the bigrade verbs, whose stems end in either -e or -i). This raises the assumption that this -a ending appears to be part of the auxiliary verb, but not part of the verb conjugation stem. (The causative auxiliary verbs 「す」 and 「さす」have same distribution and vowel arrangement.) According to this assumption, some scholars like Nicolas Tranter argue that the irrealis does not exist, per se, interpreting this instead as a more primitive "stem" plus an -a element that is the start of a following word. However, this rejection of the irrealis cannot explain the attested forms seen where the irrealis stem ending in -a is followed by the conditional particle 「ば」("if"), expressing an unreal condition (i.e. subjunctive mood) in classical Japanese.^[17] In actuality, the Japanese term 「未然形」 (mizenkei), while often translated as "irrealis", literally means "imperfect form", and it is named after this kind of usage. Additionally, the rejection cannot explain the modal auxiliary verb 「む」("seems as if, looks like, as though it should/could..."), which also attaches to the irrealis.^[18] Various examples:

Quadrigrade verb: 物(もの)に襲(おそ)はるる心(ここ)地(ち)して (The Tale of Genji)

Quadrigrade verb: 名(な)にし負(お)はばいざ言(こと)問(と)はむ (Kokin Wakashū, 411th)

Lower Bigrade: 舅(しうと)に譽(ほ)めらるる婿(むこ) (The Pillow Book)

K-irregular: 月(つき)の都(みやこ)の人(ひと)まうで来(こ)ば捕(と)らへさせむ (The Tale of the Bamboo Cutter)

Note that auxiliary verbs have their own inflections. For example, 「るる」 is the attributive of passive / spontaneous / potential auxiliary 「る」, while「らるる」 is the attributive of synonymous 「らる」 (the form attaching to bigrade verbs, whose stems end in vowels -e or -i). Additionally, both of these auxiliaries inflect according to the lower bigrade conjugation paradigm.

• The infinitive had two functions: a linking function with another yougen or auxiliary verb, and a nominal function as a deverbal noun, but these two functions have different pitch patterns.
• Generally, The yougen or auxiliary verb occurred before conjunction particle 「とも」 ("even if") in the conclusive form, but in some instances in Old Japanese poetry, the upper monograde verb 「見(み)る」 appears in the infinitive form instead before「とも」:^[19]

Man'yōgana: 之婆之婆美等母 安加無伎禰加毛 (Man'yōshū, 4503th)

Modern transliteration: しばしば見(み)とも、飽(あ)かむ君(きみ)かも

It is possible that the monograde verb infinitive form mi above that was used before 「とも」 was the earlier true conclusive form. Alternatively, the form above may have been an instance of poetic contraction to limit the number of morae on the line to the expected seven.

• Additionally, before auxiliary verb 「べし」(beshi, "should/could"), any yougen should generally use the conclusive, while R-irregular verbs use the attributive instead (「あり」 ari, 'be' at the end of a sentence but 「あるべし」 aru beshi, 'should be').^[20] With endings such as 「べし」 (beshi), there is strong evidence that this word was originally the adverb 「宜(うべ)し」 (ubeshi, "certainly"),^[21] and thus the observed combination of aru beshi is probably a fusion of the root ar- of the verb with the initial u sound of the auxiliary — suggesting that, in 「あるべし」 (aru beshi), when we would expect ari beshi, the apparently anomalous u was actually part of the following word, and not part of the verb form.

Rough classification

Voice: 'passive' and 'causative':

• Consonant-stem verbs + 「る」, vowel-stem verbs + 「らる」 (lower bigrade): passive voice; spontaneous voice (expressing lack of volitional control); honorific; potential ('can').
• Consonant-stem verbs + 「す」, vowel-stem verbs + 「さす」 (lower bigrade): causative; honorific.
• Any verb + 「しむ」 (lower bigrade): causative; honorific. It often occurs in Kanbun.

Tense/Aspect:^[22][23]

• Irrealis +「り」 (R-irregular): progressive or perfect aspect. Only attached to quadrigrade or S-irregular verbs.
• Infinitive + 「たり」 (R-irregular): progressive or perfect aspect. Attached to any verbs.
• Infinitive + 「ぬ」 (N-irregular): perfective aspect.
• Infinitive + 「つ」 (lower bigrade): perfective aspect.
• Infinitive + 「き」(unique conjugation): witnessed past tense.
• Infinitive + 「けり」 (R-irregular): unwitnessed past tense, or emotive assertion.
• Irrealis + 「まし」 (unique conjugation): counterfactual ('would have ... ed'). The combination 「ましかば」(Irrealis + ば) expresses a counterfactual condition ('if ... had ... ed').

Mood:^[22][24]

• 「む」 (quadrigrade): tentative mood, expressing among other functions uncertainty ('maybe', 'shall I?'), intention ('I shall'), and hortative ('let's').
• 「べし」 (siku-adjective): debitive mood, expressing 'can', 'should', or 'must'.
• 「なり」 (R-irregular): hearsay mood.

Polarity:^[25]

• 「ず」(unique conjugation): negative.
• 「じ」 (uninflected): negative of the tentative mood (not seem...).
• 「まじ」(siku-adjective): negative of the dubitative mood.

Mi-inflection

Ku-inflection