介绍:

speak for yourself
那是你自己的看法，我不是那样想的

Waiter：Would you like to have some pizza?
您要点些披萨吃吗？
Jerry: No one wants pizza this time.
我们这次不点披萨了。
You：Speak fo yourself！I'll have a cheese pizza with tomatoes and mushrooms on it.
那是你不要。我点一个芝士披萨，上面加番茄和蘑菇。

speak for itself
不言自明，有目共睹

I think my work these past few months speaks for itself and makes me more than qualified for this position.
我觉得过去这几个月我的工作大家有目共睹。对于这个职位我应该再合适不过。

speak up
大声说话

I'm sorry I can't hear you. Speak up, please!
不好意思听不见，麻烦大声点说.

speak one's mind
说出心里话，直抒胸臆
Can I just speak my mind, even though you probably won't like what I have to say?
我能直抒胸臆吗？或许你可能不喜欢我要说的话。