"Tanjoubi omedetou!" is a Japanese phrase and in English it means "Happy Birthday!"
Tanjoubi (pronounced as you wrote it) mean 'Birthday' in Enlish.
"Tanjoubi omedetou. Tanjoubi omedetou. Tanjoubi omedetou [name] Tanjoubi omedetou!"
'(O)tanjoubi.'
誕生日 (tanjoubi)
"Your birthday" can be translated as "Anata no [o]tanjoubi."
Tanjoubi omedetou kevin
(O)tanjoubi omedetou (gozaimasu), Hiroki The parts in brackets are not needed unless you want to be formal.
You may say 'Obaachan, tanjoubi omedetou!' In Japanese: おばあちゃん、誕生日おめでとう!
You may say '(O)tanjoubi omedetou.'お誕生日おめでとうございます => 'Otanjoubi omedetou gozaimasu' is polite and 誕生日おめでとう => 'Tanjoubi omedetou' is very casual/informal way to say 'happy birthday' in Japanese.Tanjo-bi omedeto!
'My birthday is in December' would be私の誕生日は12月にある (watashi no tanjoubi wa juunigatsu ni aru) in Japanese.You can substitute 私 (watashi) with many other pronouns such as あなた (anata),兄 (ani),彼女 (kanojo), etc.あなたの誕生日は12月にある (anata no tanjoubi wa juunigatsu ni aru) - "Your birthday is in December."
"watashi no okurebase nagara tanjoubi omedetu"