We just learned that in Greek I am happy is Είμαι χαρούμενος (eímai charoúmenos).
Now let's learn how to say You are sad.
Είσαι λυπημενος (Eísai lypimenos)
We can break it up into two words:
You are - Είσαι (Eísai) - sounds like EE-say
sad - λυπημενος (lypimenos) - Sounds like lee-pee-may-noh-s
So all together Είσαι λυπημενος sounds like EE-say lee-pee-may-noh-s.
(from: wikipedia - center for the greek language)
ASL: You are sad
Italian: Sei triste
German: Sie sind traurig
Spanish: Estas triste
French: Vous êtes triste