Sixty-first birtday is "kuudeskymmenesyhdeksäs syntymäpäivä" in written language, but it is often shortened in speech, and usually you can just say Happy birthday! without mentioning which birthday it is. In spoken language it would be more natural to say "kuuskytyhdeksäs syntymäpäivä".
The Finnish language is suomi (Finnish) or suomen kieli (Finnish language) in Finnish.
Finnish legend in Finnish is "suomalainen legenda".
I am not Finnish. - (Minä) en ole suomalainen.
The plural of Finnish Spitz is "Finnish Spitz".
Helki is not Finnish
For you is sinulle in Finnish.
How is miten in Finnish.
Finnish
Finnish is spoken in Finland.
You are Finnish: "Sinä olet suomalainen." I am Finnish: "Minä olen suomalainen." Suomalainen is spelt with a lower case s.
Stockings are sukkahousut in Finnish.
That word is not Finnish.