Appendix D — Verb Conjugation Tables

This appendix collects every conjugation pattern introduced in Stage 1 into a single reference. Each verb is shown in all five forms covered: 辞書形 (dictionary form), ます-forms (affirmative, negative, past, past-negative), ない-form, た-form, and て-form. No new grammar is introduced here — this is purely for quick lookup.

D.1 五段動詞 (Consonant-Stem Verbs)

Five-row verbs are shown one per ending type. Each table gives the full set of Stage 1 conjugations.

かく (to write) — く-ending

およぐ (to swim) — ぐ-ending

はなす (to speak) — す-ending

まつ (to wait) — つ-ending

しぬ (to die) — ぬ-ending

あそぶ (to play) — ぶ-ending

のむ (to drink) — む-ending

かう (to buy) — う-ending

Note: う-ending verbs are the only 五段 verbs whose ない-form changes the vowel in an unexpected way: the う becomes わ, not あ. This is because the verb stem ends in a consonant /w/ that only surfaces before the あ-row vowel.

つくる (to make) — る-ending (五段)

This verb ends in る but is 五段, not 一段. The sound before る is in the う-row (くる), not in the い-row or え-row. This is exactly the kind of verb where class identification matters — conjugating it as 一段 would produce incorrect forms.

いく (to go) — Exception

いく is a く-ending 五段 verb and is regular in every form except た-form and て-form. A regular く-ending verb would give いいた and いいて; instead, いく uses いった and いって, following the つ/る/う pattern. This is the only く-ending verb with this irregularity. The ます-form and ない-form are entirely regular.

D.2 一段動詞 (Vowel-Stem Verbs)

All 一段 verbs conjugate identically: drop る from the dictionary form, then attach the appropriate ending. There are no sub-types, no variation by preceding sound, and no exceptions.

たべる (to eat) — え-row 一段

みる (to see / to watch) — い-row 一段

おきる (to wake up / to get up) — い-row 一段

D.3 不規則動詞 (Irregular Verbs)

Japanese has exactly two irregular verbs. Their forms must be memorized individually.

する (to do)

All する-compound verbs follow this pattern. The noun portion remains unchanged; only する conjugates.

べんきょうする (to study) — する-compound

くる (to come)

くる is the only verb in the language whose stem vowel changes across conjugations: く in the dictionary form, き in the ます-form and た/て-forms, こ in the ない-form. There is no pattern to extract — memorize the three shapes.

D.4 五段動詞 Conjugation Rules — Master Summary

This table shows how each 五段 ending transforms across all Stage 1 forms. The 一段 and irregular patterns are included at the bottom for completeness.

Exception: いく → いった / いって (not いいた / いいて)

D.5 音便 (Sound Change) Groupings

The た-form and て-form changes in 五段 verbs are driven by 音便 (おんびん) — euphonic sound changes. The nine endings fall into four groups:

Note the voicing distinction within イ音便: く-ending verbs give いた/いて (unvoiced), while ぐ-ending verbs give いだ/いで (voiced). The voicing of the original ending carries through.

D.6 Adjective Conjugation Summary

Adjectives are not verbs, but they conjugate in Japanese. Stage 1 covers the following forms for both types.

い-adjective paradigm

Using たかい (expensive / tall) as the representative example:

Transformation rule: remove い from the dictionary form to get the stem (たか～), then attach the appropriate ending.

Exception: いい (good) uses an irregular stem よ～ for all forms except the plain non-past:

な-adjective paradigm

Using しずか (quiet) as the representative example:

Transformation rule: な-adjectives conjugate identically to nouns with the copula. The adjective stem itself never changes — only the copula (だ/です) conjugates.

D.7 Noun + Copula Conjugation

For completeness, the copula (だ / です) paradigm used with nouns. This is structurally identical to な-adjective conjugation.

Using がくせい (student) as the representative example:

D.8 Quick-Reference: Identifying Verb Class

When encountering an unfamiliar verb in dictionary form, use this decision procedure:

1. Is it する or くる? → Irregular.
2. Does it end in a noun + する? (e.g., べんきょうする, さんぽする) → する-compound (irregular).
3. Does it end in る with an い-row or え-row sound before る? → Likely 一段. (But check for known 五段 exceptions like かえる "to return," はいる "to enter," はしる "to run," きる "to cut.")
4. Everything else → 五段.

This heuristic is reliable but not infallible. A small number of verbs ending in -いる or -える are 五段 rather than 一段. These must be learned individually. Dictionaries mark verb class; when in doubt, look it up.

This appendix covers all verb, adjective, and copula conjugation patterns introduced in Stage 1. For potential forms, volitional forms, conditional forms, passive forms, and causative forms, see Stage 2 and beyond.