Japanese Verb Stems Overview

Overview

This lecture explains the five main Japanese verb stems, focusing on their conjugations and how they combine with helper verbs/adjectives, with examples and key grammar rules.

Japanese Verb Basics

• Japanese verbs end with a kana from the う-row and have five possible stem forms (based on the five vowels).
• Conjugations enable attachment of helper verbs/adjectives, not direct changes in meaning.

The い-stem (連用形, Connective/masu form)

• The い-stem attaches to helper verbs/adjectives like ます (politeness) and たい (desire).
• Examples: 飲み + たい = 飲みたい, 使い + たい = 使いたい, 話し + たい = 話したい.
• For Ichidan verbs, drop る: 食べる → 食べたい.
• The い-stem can attach to nouns: 飲み物 ("beverage"), 使い方 ("way of using").
• Used to nominalize verbs: 休む → 休み ("a rest").

The あ-stem

• Mainly used for negatives by attaching ない, ず, or ぬ: 知る → 知らない, 知らず.
• Negative for Ichidan verbs: drop る, add ending (食べる → 食べない).
• う-ending verbs replace う with わ (e.g., 買う → 買わない).
• Attaches receptive (れる/られる) and causative (せる/させる) forms: 飲まれる ("is drunk"), 飲ませる ("make drink").
• Ichidan verbs: use られる (receptive) and させる (causative).

The え-stem

• Used for imperatives/commands: 飲む → 飲め ("Drink!"), 使う → 使え.
• Ichidan verbs: add ろ or よ (起きる → 起きろ).
• For conditionals, add ば: 飲めば ("if drink"), 食べれば ("if eat").
• Potential form: add る (飲める = "can drink"); Ichidan: られる (食べられる = "can eat"), or with ら抜き: 食べれる.

The お-stem

• Forms volitional ("let's...") by adding う: 飲もう ("let's drink"), 話そう ("let's talk").
• Ichidan verbs: add よう (食べよう).

Combining Stems and Forms

• Complex forms are made by combining stems and helper verbs sequentially (e.g., causative + passive + negative + past).
• Treating each helper and stem separately clarifies conjugation logic.

Sentence Structure Insights

• The sentence's final word (verb/adjective) determines its structure, affecting particles like を and が.
• Example: ビールを飲む (“to drink beer”) vs. ビールが飲みたい (“want to drink beer”).

Key Terms & Definitions

• Godan verb — Verbs changing last kana across five vowel rows.
• Ichidan verb — Verbs that drop る for most conjugations.
• い-stem (連用形) — Connective stem; attaches helper words or nominalizes.
• あ-stem — Used for negatives, causative, and passive forms.
• え-stem — Used for imperatives, conditionals, potential form.
• お-stem — Volitional (“let’s”) form.
• Helper verb/adjective — Words like ます (politeness), たい (desire) added after stems.
• Nominalization — Turning a verb into a noun (e.g., 休み from 休む).

Action Items / Next Steps

• Practice stem conjugations using Don's Japanese conjugation drill website.
• Watch the linked videos on the て-form and explanation of を particle and subjectivity in Japanese.