Enjoy your meal in your language

Mine is hyvää ruokahalua

Bon appétit (French)
Traditionnally, nothing is said in Breton, but nowadays, it seems Kalon digor appears in dictionnaries.

Note : "Bon appétit" is used in French, but it's a lack of etiquette to say such thing to someone. Bon appetit is something physical and related to food or animals, yet you are supposed to be civilized and to eat for your enjoyment, not because you strictly need it to survive.

tl;dr : "Bon appétit" lacks of refinment.

in italian it’s “buon appetito” 🍴

Schmecken lassen!
Haut rinn!
Los schmeckos!
Miracoli ist fertig!
Auf die Teller, fertig, los!
Piep, piep, piep, guten Appetit!

In spanish is "provecho"! 🙂

"Gudden Appetit" in Luxembourgish

Schmecken lassen!
Haut rinn!
Los schmeckos!
Miracoli ist fertig!
Auf die Teller, fertig, los!
Piep, piep, piep, guten Appetit!

Miracoli ist fertig! 😂😂😂 der ist gut!

"Смачного!" in Ukrainian language.
It sounds like " Smachnogo!" 😄

Chinese：用餐愉快！
Yong Can Yv Kuai

In turkish, "Afiyet olsun!" 🙂

In polish "Smacznego" 🙂

It depends on the culture! But, mainly we say:

استمتع بوجبتك
صحتين وعافية or صحة وعافية

Other Arab countries say:
صحة وهنا
بالهنا والشفا
مطرح ما يسري يمري
كل واشكر
هنيئا مريئا
etc...

In Swedish "smaklig måltid" ("smaklig" = tasty, måltid = meal)

"Eet smakelijk" in Dutch

'ä guätä' in Swiss German 😁