Dear Liebert William from China No stupid questions, but only stupid answers. 走 basically means to walk, this is correct. But it also means leave, like 快走， it means leave here asap. What your doubt is acceptable, too. People can understand that if you say so. When you say: Let's walk. basically means let's go for a walk, specifically refers to walk.only. However, obviously, let's go does not means let's go for a walk. Generally,it means let us leave here and go to the destinaton. right? 我们去吧，this inclines that you have a clear destination to go, you know 去 where, like 去学校，饭店，等等。 我们走吧，it does not care whether you have a destination, it inclines that you just want to leave the place you are now in, and know or do not know where to reach. So 我们走吧 includes the meaning of 我们去吧。 All in all, 我们走吧 is better to translate let's go. and it is more common used and idiomatic. Hope you get it now!

走 also means "go"

both are right!我们走吧and 我们去吧 both are right,去focuses on direction, 走focuses on feet, but in a real life there is no difference, you may drive , you may run ,you may ride a bike, you may walk after you say我们走吧！

That's a simple but interesting question. Do you ever think about why don't we use "small" to express "large" but use "big"? it's just the language custom that we inherit from our ancestors.

Let's go in Chinese is 我们走吧， not 我们去吧