1. Speak Up

根据格林斯双语字典，有两种比较多用的含义：

1.） If you speak up, you say something, especially to defend a person or protest about something, rather than just saying nothing. 有为什么人或者什么事情，挺身而出 辩解和维护的意思。可以为自己的观点speak up，也可以帮助别人speak up。

2. ） If you ask someone to speak up, you are asking them to speak more loudly. 这个就很简单，要求别人大声说话。

2. Talk up

If someone talks up a particular thing, they make it sound more interesting, valuable, or likely than it originally seemed，有夸大，和为了达到某种目的赞美的意思。