Polite vs Casual Japanese: です/ます and Plain Forms You’ll Actually Use

Ever wonder why your Japanese friends say 行く but your teacher says 行きます? Japanese has two everyday styles: polite (です／ます) and casual (plain). Today we’ll make them feel natural, so you can switch smoothly—at work, with teachers, and with friends.

The two everyday styles

Polite style: use です with nouns/adjectives and ます with verbs.
Casual (plain) style: use dictionary forms (食べる・行く) and だ with nouns/na-adjectives. With i-adjectives, just the adjective (かわいい・忙しい) is fine.

Think of polite as “safe for anyone” and casual as “for friends and equals.”

Japanese

私は学生です。

I am a student.

Japanese

私は学生だ。

I’m a student. (casual/blunt)

ですです

to be (polite copula)

copula

今日は静かです。

It’s quiet today.

だだ

to be (plain copula; can sound blunt)

copula

この店は安い＋だ → この店は安い。（i-adjective doesn’t take だ）

This shop is cheap. (i-adjective)

丁寧 polite, courteous 語 language/words

Quick practice: choose the right ending

Use です for polite statements with nouns/na-adjectives. Try these:

田中さんは先生。

このへやは静か。

わたしは学生だです。 → わたしは学生です。 Never mix だ and です. Use 学生です (polite) or 学生だ (casual).

Verbs: ます vs dictionary form

Polite verbs use ます. Casual verbs use the dictionary form. Negative and past also change:

食べる present & past

Pronoun	Conjugation
present (polite)	食べます
present (plain)	食べる
negative (polite)	食べません
negative (plain)	食べない
past (polite)	食べました
past (plain)	食べた

Japanese

毎日、野菜を食べます。

I eat vegetables every day. (polite)

Japanese

毎日、野菜を食べる。

I eat vegetables every day. (casual)

あした、東京に行。

仕事に行くます。 → 仕事に行きます。 Add ます to the verb stem: 行き + ます (not 行くます).

Adjectives: small change in polite style

i-adjectives: add です to be polite (暑い → 暑いです).
na-adjectives: add です (静か → 静かです). Casual style often drops です.

Japanese

今日は暑いです。

It’s hot today. (polite)

Japanese

今日、暑い。

It’s hot today. (casual)

今日は寒い。

ねね

sentence-ending particle (seeking agreement)

particle

暑いですね。

It’s hot, isn’t it?

よよ

sentence-ending particle (giving information/assertion)

particle

このラーメン、おいしいよ。

This ramen is tasty, you know.

When to use which (cultural notes)

Polite (です／ます): first time meetings, teachers, bosses, shops, customer service, emails.
Casual (plain): close friends, family, classmates you know well.

Name + さん (田中さん) is polite. Using だ with strangers or teachers can sound rude. With i-adjectives in casual speech, don’t add です.

さんさん

Mr./Ms. (polite suffix)

suffix

田中さん、こんにちは。

Hello, Ms./Mr. Tanaka.

友だちともだち

friend

noun

友だちと話すとき、よくカジュアルに話します。

When speaking with friends, we often speak casually.

上司じょうし

boss/superior

noun

上司には丁寧に話します。

We speak politely to our boss.

Arrange a polite conversation

Put the lines in a natural order for a shop interaction.

💬 In a ramen shop

Build a casual sentence

Reorder the words to form a natural casual sentence.

🔠 Put the words in order

Plain form (dictionary) at the end in casual style.

Polite and casual pairs you’ll use a lot

Japanese

これはおいしいです。

This is delicious. (polite)

Japanese

これ、おいしい。

This is delicious. (casual)

Japanese

学校に行きます。

I go to school. (polite)

Japanese

学校に行く。

I go to school. (casual)

忙しいだ。 → 忙しい。／忙しいです。 i-adjectives don’t take だ. Use the adjective alone (casual) or add です (polite).

Mini-quiz: choose polite or casual

Pick the best option for the situation or the correct transformation.

🧠 Polite vs Casual A2 Check

Quick summary

Use です／ます for polite speech; plain forms for casual.
Nouns/na-adjectives: 学生です (polite) / 学生だ (casual).
i-adjectives: 暑いです (polite) / 暑い (casual).
Verbs: 行きます (polite) / 行く (casual). Negative: 行きません / 行かない.
With strangers, teachers, or at work—stay polite. With friends—casual is fine.

Final practice: speak it out

At a café: 「コーヒーをお願いします。ありがとうございます。」
With a friend: 「今日、映画見る？うん、見よう。」

Keep listening for です／ます in formal situations and plain forms with friends. With practice, switching styles will feel automatic. がんばって！