"be well" is not something you would say to a Hebrew speaker. The closest phrase you could use is kol tuv (כל טוב) which means "all the best".
sleep well = lee-SHOHN TOHV (לישון טוב)
You would say "hah-m'dah-BEHR ah-TEM eev-REET ?" We're curious ... If you don't know how to say that, then why would you ever need to ??
ha-alefbet ha-ivri (האלפבית העברי)
to a male: atah medaber ivrit (אתה מדבר עברית)to a female: aht medaberet ivrit (את מדברת עברית)