Verb Groups and Polite Conjugation

Introduction to Japanese Verbs and the Polite Form

In Japanese, the base form of every verb listed in the dictionary ends with an 'u' vowel sound (such as u, ku, su, mu, or ru). This basic form is called the dictionary form or plain form. While native speakers frequently use this form with close friends and family, beginners should first master the polite form, often called the 'masu form' (ます形, masu-kei).

Using the -masu form shows respect and social distance, making it appropriate for talking to teachers, colleagues, acquaintances, and service staff. To turn a dictionary verb into its polite -masu form, you must first know which of the three verb groups it belongs to: Group 1 (Godan), Group 2 (Ichidan), or Group 3 (Irregular).

Group 2 Verbs (Ichidan Verbs)

Group 2 verbs are the easiest to conjugate. In Japanese, they are known as 一段動詞 (ichidan doushi). All Group 2 verbs end with the syllable る (ru) in their dictionary form, and the vowel sound immediately preceding that る (ru) is almost always an 'i' sound or an 'e' sound.

To conjugate a Group 2 verb into the polite form, simply drop the final る (ru) and attach ます (masu). For example, 食べる (taberu, to eat) becomes 食べます (tabemasu, I eat / I will eat). Similarly, 見る (miru, to see / to watch) drops the る to become 見ます (mimasu), and 寝る (neru, to sleep) becomes 寝ます (nemasu).

Group 1 Verbs (Godan Verbs)

Group 1 verbs are known as 五段動詞 (godan doushi). This group contains verbs with various endings: う (u), く (ku), ぐ (gu), す (su), つ (tsu), ぬ (nu), ぶ (bu), む (mu), and る (ru). Unlike Group 2, if a Group 1 verb ends in る (ru), the preceding vowel sound is usually an 'a', 'u', or 'o' sound (for example, とる / toru, 'to take').

To conjugate a Group 1 verb into the -masu form, change the final 'u' vowel sound of the verb to its corresponding 'i' vowel sound, and then add ます (masu). For example: 書く (kaku, to write) ends in 'ku', so change 'ku' to 'ki' to make 書きます (kakimasu). 飲む (nomu, to drink) ends in 'mu', so change 'mu' to 'mi' to get 飲みます (nomimasu). 話す (hanasu, to speak) changes 'su' to 'shi' to become 話します (hanashimasu).

Watch out for a handful of common exceptions! A few verbs end in an 'i' or 'e' vowel before る (ru) but actually belong to Group 1. The most common JLPT N5 exception is 帰る (kaeru, to return home), which conjugates as 帰ります (kaerimasu), not kaemasu. Another common example is 入る (hairu, to enter), which becomes 入ります (hairimasu).

Group 3 Verbs (Irregular Verbs)

There are only two irregular verbs in standard Japanese: する (suru, to do) and 来る (kuru, to come). Because their stems change unpredictably, their polite forms must be memorized individually.

The verb する (suru) becomes します (shimasu). This verb is extremely versatile because you can attach it to many nouns to create compound action verbs: for instance, 勉強 (benkyou, study) + する (suru) becomes 勉強します (benkyou shimasu, to study), and 買い物 (kaimono, shopping) becomes 買い物します (kaimono shimasu, to shop).

The verb 来る (kuru) changes both its spelling and its reading in polite form. The kanji 来 remains, but its pronunciation changes from 'ku' to 'ki', resulting in 来ます (kimasu, to come). For example: 友だちが来ます (Tomodachi ga kimasu, A friend will come).

The Four Polite Tenses

Once you have the verb stem (the part before ます), you can easily express past and negative actions by swapping the ending. Japanese verbs do not change based on person (I, you, he, they), and the present tense also functions as the future tense.

The four polite endings are: Present Affirmative (-masu), Present Negative (-masen), Past Affirmative (-mashita), and Past Negative (-masen deshita). For instance, with 食べます (tabemasu, eat): 食べません (tabemasen, do not eat / will not eat), 食べました (tabemashita, ate), and 食べませんでした (tabemasen deshita, did not eat).

Consider this complete example sentence: 昨日の夜、お茶を飲みました (Kinou no yoru, ocha o nomimashita - Last night, I drank green tea). Here, the object marker を (o) marks 'ocha' (tea), and 飲みました (nomimashita) expresses the polite past action.