Hyvää syntymäpäivää!
¡Feliz cumpleaños!
生日快乐！
!יום הולדת שמח
Feliz Aniversário!
Buon compleanno!
誕生日おめでとう！
Happy Birthday!

(I'm not sure if I got the Japanese version right because I had to look it up on the web, but in any case, I hope you two have a great year!)