YOU SAID:

My friends are so stupid

INTO JAPANESE

私の友達はとても愚かです

BACK INTO ENGLISH

My friends are very stupid.

INTO JAPANESE

私の友達はとても馬鹿だ。

BACK INTO ENGLISH

My friend is very stupid.

INTO JAPANESE

私の友人はとても馬鹿だ。

BACK INTO ENGLISH

My friend is very stupid.