わたし は事院寺院へ いきますした!

たのしかった! またはへんてこ（な感じがしました） ... みなベトナム語をはなします(Vietnamese). ごめん でも..I don't know how to say Vietnamese or Vietnam in Japanese.

へんてこ is a very casual noun. so would be more natural if you add "なかんじがしました。" which means I felt adj. 

Also as gardeninafly mentions, Vietnamese is ベトナム語(べとなむご)

easy tip is if you wanted to say language which is spoken in a country, usually just "name of a country" + 語（ご） :) for example, ロシア語(russian), ちゅうごく語（chinese).

of course there are so many exceptions like English, Hindu. 

if there is any questions, just please feel free to ask me :)

Kaori