Polite vs Casual Japanese: です/ます and Plain Form
✍️ Mori-sensei · Japanese Teacher · Updated 2026-06-22
Japanese sentences come in two main registers: polite and casual. The polite register uses です and ます; the casual register uses plain forms like だ and the dictionary form of verbs. Knowing which to use, and when, is one of the most useful skills a beginner can build.
The two registers
The polite register, called teineigo, ends statements with です (for descriptions) or ます (for verbs) — for example, 食べます ("I eat") and 学生です ("I am a student"). It is the safe, neutral way to speak to almost anyone.
The casual register, or plain form, uses だ instead of です and the plain dictionary form of verbs — for example, 食べる ("eat") and 学生だ ("am a student"). It sounds relaxed and familiar, the way you would speak with people close to you.
When to use which
Use the polite です/ます register with strangers, people older or more senior than you, customers, and almost everyone at work or school. It is the default for any situation where you want to show respect or simply play it safe.
Use the casual plain form with close friends, family, and people clearly younger or of equal standing who you know well. Switching to casual too early can sound rude, so when in doubt, stay polite — over-politeness is rarely a problem.
Why courses start with polite
The JLPT and most structured courses, including ours, teach the です/ます register first. It is grammatically regular, it is acceptable in nearly every situation, and it lets you speak with real people from day one without causing offence.
Plain form is introduced soon after, because you need it to read casual writing, follow conversation among friends, and build many grammar patterns. Learning polite first, then casual, is the path that keeps you safe while you grow.
Frequently asked questions
Is です/ます or plain form harder?
Neither is truly harder — they are two registers of the same grammar. Beginners usually find です/ます easier to start with because the endings are regular and you can use it almost anywhere without worrying about offending someone.
What is keigo, and is it the same as polite Japanese?
Keigo (敬語) is a further, more advanced layer of honorific and humble language used to show extra respect — for example, to customers or senior colleagues. Everyday です/ます politeness is the foundation; keigo builds on top of it and is usually studied later.
Can I just use polite Japanese all the time?
Yes, です/ます is acceptable in almost every situation and will never sound rude, so it is a safe default. You will still want to understand plain form so you can follow casual speech and reading, even if you mostly speak politely yourself.