Thanks, and the Answer to Thanks
Kiitos is thank you. It is also please — Finnish has no separate word for it, so kiitos does both jobs depending on where it sits.
The reply is ole hyvä, literally "be good", which doubles as here you are when handing something over. Ei kestä — literally "it does not last" — is the more casual don't mention it.
Sorry, and the Answer to Sorry
Anteeksi covers everything English splits between sorry and excuse me. You use it to apologise, to get past someone, and to open a question to a stranger.
The standard reply is ei se mitään — "it's nothing", never mind.
Yes, and How Finns Actually Say It
| word | register |
|---|
| kyllä | neutral, and the one you write |
| joo | casual, and what you will hear far more often |
| selvä | "okay, got it" — agreement rather than yes |
Kyllä is not wrong in speech, but a Finn answering a friend says joo. Learn both.
Mitä kuuluu? is how are you? — literally "what is heard?". It is a real question in Finland, not a passing noise, and it expects an actual answer.
Hauska tutustua is nice to meet you, and kiitos samoin is the all-purpose thanks, likewise — the reply to any good wish at all.