'Tusen' means 'thousand'.
Tusen takk is Norwegian for thank you.
tusen
In Norwegian, you would say "tusen takk" to mean 'thank you very much'.
"Tusen takk, kjære" or "Takk, kjære"
That would be "Tusen takk for bursdags ønskene"
Jo Stein Moen has written: 'Tusen dager' -- subject(s): Norwegian Participation, Norwegian Foreign public opinion, Foreign relations, History
Thorvald Stoltenberg has written: 'De tusen dagene' -- subject(s): Diplomatic history, Norwegian Participation, Participation, Norwegian, Peace, Yugoslav War, 1991-1995
"Tusen takk kjære venn" means "thank you dear friend". It's a statement, not a question, and doesn't have a general answer or response.
Nu tändas tusen juleljus was created in 1898.
That would be "Tusen takk for bursdags ønskene"
Tusen takk. (too-sehn tahk) Literally "a thousand thanks".
That is not a Norwegian word.