Late Middle Japanese

[1] It was a period of transition in which the language shed many of its archaic features and became closer to its modern form.

Accompanying that change, the nation's political center temporarily transitioned from historical Kyoto to Kanto alongside the establishment of the Kamakura shogunate.

This move resulted in a significant blend between the dialects of Kyoto and Kanto, shaping the language of the time.

[4] In an attempt to spread Christianity among the locals, many Portuguese missionaries studied Japanese, producing a number of dictionaries and linguistic grammars such as the Arte da Lingoa de Iapam and Nippo Jisho, in addition to producing translations of Japanese literary works.

Initially, /e/ and /o/ were realized with semivowels [j] and [w], respectively,[dubious – discuss] a result of earlier mergers inherited from Early Middle Japanese.

The sibilants /s, z/ were palatalized before /i/ and /e/ and had the following distribution:[11] João Rodrigues noted in Arte da Lingoa de Iapam that the eastern dialects were known for realizing /se/ as [se], rather than [ɕe].

/t/ and /d/ were distinguished from the sibilants in all positions but undergo affrication before /i, u/: Voiced stops and fricatives were prenasalized:[14] João Rodrigues made that observation in Arte da Lingoa de Iapam.

In addition, the Korean text Ch'ŏphae Sinŏ spelled [...] b, d, z, g with the Hangul letter sequences -mp-, -nt-, -nz-, -ngk-"[11] indicating prenasalization.

[10][24][18] -m > -mm-: -n > -nn-: -t > -tt-: Onbin (音便, "euphony") are a type of sporadic sound changes and "were not automatic or exceptionless," [25] and their exact causes are still debated.

They also appear in earlier stages of the language but were particularly prevalent throughout Late Middle Japanese and had a great effect on its verbal and adjectival morphology.

One of the most prominent developments was the replacement of the conclusive form by the attributive,[27] which has a number of effects: Late Middle Japanese inherited all nine verbal conjugations from Early Middle Japanese: However, throughout the period, bigrade verbs gradually changed into monogrades.

The process was completed by Early Modern Japanese, partly a result of the merger of the conclusive and attributive forms.

The regular adjective was traditionally subdivided into two types: those whose adverbial form ends in -ku and those whose ends in –siku:[29] There were three notable changes that eventually collapsed the two-way distinction into one: While the grammatical distinction between the two classes has disappeared, the historic distinction was used to explain certain present forms of -shii adjectives, notably the euphonic changes (音便) that occur in polite form of adjectives (when they are followed by ござる gozaru 'to be' or 存じる zonjiru 'to know').

During Late Middle Japanese, -i was attached to lower bigrade, k-irregular, and s-irregular verbs:[32] João Rodrigues Tçuzu noted in Arte da Lingoa de Iapam that -yo could be replaced with -ro, as in miyo > miro "look.