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".
Helki is not Finnish
I am not Finnish. - (Minä) en ole suomalainen.
The plural of Finnish Spitz is "Finnish Spitz".
For you is sinulle in Finnish.
How is miten in Finnish.
Finnish is spoken in Finland.
Finnish
You are Finnish: "Sinä olet suomalainen." I am Finnish: "Minä olen suomalainen." Suomalainen is spelt with a lower case s.
That word is not Finnish.
Stockings are sukkahousut in Finnish.