Verb stems As a result of onbin changes, consonant-stem verbs developed variant "onbin stems" used before certain suffixes (in modern Japanese, the past , gerund , conditional , and representative ). Consonant-stem verbs are those that can be analyzed as having underlying stems that end in a consonant (in modern Japanese, any of ): these verbs take the suffix in the dictionary form, in contrast to vowel-stem verbs, which have stems that end in either or and take the suffix in the dictionary form. In Japanese grammatical terminology, consonant-stem verbs are called verbs, because their inflected forms make use of the five kana that represent the stem-final consonant plus each of the five Japanese vowels (). Verbs with stems ending in show an additional complication: stem-final is deleted before suffixes that start with , since Japanese phonotactics only allow to occur before the vowel . In terms of historical development, verb stems that end in originally ended in the consonant *p. The onbin stem developed from the Early Middle Japanese infinitive () form, which ended in . When the infinitive form of a consonant-stem verb ended in one of the syllables , it could undergo the
onbin sound changes described above. In addition, it came to be possible for to undergo analogous changes in this context: thus, could become (as in > , > ) and could become (as in > ). argues that verbs with stems ending in developed onbin stems purely as a result of the morphological process of analogy, rather than as a result of the same phonetic processes as the other onbin changes. In modern Standard Japanese, the form of a verb's onbin stem can typically be predicted from the underlying stem-final consonant: give , give (with voicing of the following to in the suffix), gives , and gives (with voicing of the following to in the suffix). Verbs with underlying stems ending in do not show onbin in contemporary standard speech, but instead use () before the relevant suffixes. : is the only n-stem verb in modern Japanese. A few verbs have an exceptionally formed onbin stem. For example: • the verb (stem ) has an onbin stem in , e.g. , rather than the expected . • the verbs and (stems , , originally -, -) have u-onbin stems, e.g. , , rather than the expected . • the honorific verbs , , , , and all exhibit an i-onbin stem prior to the polite auxiliary verb , e.g. , , etc., rather than the expected non-onbin form . These verbs have the expected onbin forms before suffixes , , , . Dialects show some differences in the formation of onbin stems. Some dialects regularly use u-onbin (with fusion of to ) for verb with underlying stems that end in (where standard Japanese has Q-onbin) or verbs with underlying stems that end in (where standard Japanese has N-onbin). • Use of u-onbin for verbs with stems that end in (original ) is a feature of dialects spoken in western regions, such as
Kansai (including Kyoto) and Kyushu. For example, in the Kyoto dialect the verb (stem ) has the past form , in contrast to standard Japanese . The 17th-century
Arte da Lingoa de Iapam by
João Rodrigues identified the use of u-onbin in this context as a feature of the Japanese spoken in Kyoto, in contrast to the use of Q in the Kanto dialect. • Use of u-onbin for verbs with stems that end in is found on Kyushu and in the far west of Honshu; in contrast, in Kyoto and most of Kansai, these verbs currently show consonantal onbin as in the standard language. For example, in some dialects the verb (stem ) has the gerund form , in contrast to (used in standard Japanese and in the Kyoto dialect). The voicing of the suffix to indicates that these u-onbin forms originally contained nasalized . • Use of i-onbin for verbs with stems that end in survives dialectally in some regions, including much of Kansai (although not in Kyoto). Thus, forms such as can occur in place of standard for the gerund of the verb (stem ). • Some dialect forms show consonantal onbin in verbs with stems ending in or , where standard Japanese has i-onbin. The use of onbin stems in inflected verb forms never become normative in
literary written
Classical Japanese. It is difficult to tell how frequent they were in speech at various historical periods. , citing , gives the following chronology for the written attestation of onbin in verb forms: • to : seen from the late 9th century. • to : rarely seen until the mid 10th century, from which point it is found regularly. • (original ) to : seen from the first half of the 11th century. • to : seen sporadically from 11th century, becoming regular at the end of the 16th century. However, suggests that onbin changes must have been active well before these dates, arguing that they precede
the intervocalic merger of and (dated at the latest to the end of the 10th century) and most likely began in the early 9th century or even the late 8th century.
Adjective endings Two suffixes used in the inflection of adjectives underwent onbin changes. The
Old Japanese adnominal ending developed by onbin into the Late Middle Japanese and Modern Japanese nonpast ending , as in , the nonpast form of the adjective stem . The adjectival infinitive ending developed an onbin variant : however, remains the normal form of this ending in Standard Japanese. The use of (which fuses with the preceding vowel) as an adjectival infinitive ending is a characteristic of the language spoken in the Kansai (including Kyoto) and Kyushu regions. Using the adjective again as an example, the Kansai dialect form corresponds to the Standard Japanese infinitive . The pronunciation of the adjectival infinitive ending as in Kyoto vs. in the Kanto region is mentioned as a dialectal difference in Rodrigues'
Arte da Lingoa de Iapam. The variant ending shows some limited use in Standard Japanese as part of the rarely used "super-polite" construction (which occurs when the adjective is followed by the copula ) and in a few isolated, fixed expressions: its use in these contexts can be attributed to borrowing from the Kyoto dialect. ==Phonetic development==