''Ευτυχισμένα γενέθλια'', ''Χρόνια πολλά'' It is just unappropriate to write greek in latin writing system. Greek language has its own alphabet.

Hello Noah, Happy Birthday in Greek : Eytyxismena Genethlia! or Chronia Pola!

عيد ميلاد سعيد كل سنة وانت طيب\ ـة