Noriです vs だ: polite vs plain, not 'formal vs slang'
です vs だ is not "correct vs incorrect." It's which room you're in.
がくせいです is the polite way to say you are a student. がくせいだ is the same fact, plain. You'd use です with a teacher, a clerk, almost anyone you just met. だ belongs with friends, diaries, and later grammar that builds on the plain form.
Beginners get told だ is slang. It isn't. It's the default dictionary shape. Polite speech adds です / ます. You still need だ later for だから, だけど, and quoting.
Practice this in five minutes, not another Anki deck.
Nori is a beginner Japanese app with tiny grammar quizzes and a waitlist before launch.
For week one, speak です. When you read manga or tweets, notice だ without copying it into a job interview.
If someone asks "are you a student?" the polite answer is はい、がくせいです — not a lecture on copulas. One form, one room, then stop.
です is polite 'is.' だ is plain 'is.' Use です with people you don't know well. だ shows up in casual speech and inside other grammar. Same fact, different register.
Ready for five minutes of Japanese?
Tiny grammar bites, tap-to-reveal quizzes, no streak shame. Join the waitlist.