tease和sarcasm用法有什么不一样?都有insult的意味么?

Yes!

tease是戏弄; 取笑, 逗弄的意思，口语用的多
sarcasm是挖苦, 讽刺的意思，书面用的多

tease地解释：
a: to disturb or annoy by persistent irritating or provoking especially in a petty or mischievous way
b: to annoy with petty persistent requests : pester; also : to obtain by repeated coaxing
c: to persuade to acquiesce especially by persistent small efforts : coax
d: to manipulate or influence as if by teasing
e: to make fun of : kid
综上，tease的意思多半含有非恶意的淘气，取闹行为，注意，是persistent，就是不断的闹，戏弄
但是，总体来说，不一定是贬义

但是，sarcasm就是很贬义的，含有恶意的挖空，捉弄了

tease没有insult的意思, 但是也不是善意的玩笑, 应该是介于两者的程度之间

不过sarcasm就是纯粹的挖苦, 讽刺, 是很不厚道的行为.