In Turkish culture is important to say “çok yaşa” when someone sneezes infront of you. Çok yaşa means “long live” in English. Of course its a kind wish for that person. ıt means exactly i hope you will live long. If someone says to you “Çok yaşa” you need to response to that wish sentece. You can response with “sen de gör“, “siz de görün” or “hep beraber“. Lets look at that senteces meanings in English.
Sen de gör: I hope you will see too.
Siz de görün: I hope you will see too. (in offical way or for plural person)
Hep beraber: All together. It means we all see together.
Also for “çok yaşa” there is alternative sentences. We said before its a wish so it can change. For example you can say “mutlu yaşa” (live happy in eng.), “iyi yaşa” ( live good) etc. instead of “çok yaşa”.