- let us (dated)
- (inclusive) Used to form the hortative of verbs, equivalent of the first-person plural imperative in some other languages.
- Let’s eat lunch sometime.
- Let’s dance.
- (exclusive) Used to form the hortative of verbs, equivalent of the second-person plural imperative in some other languages, chiefly instructional
- Let’s make sure we don't forget proper punctuation.
- Hey guys, let’s check to make sure that we proofread.
- Y'all, let’s stop talking please, y'all are driving me up the wall!
Let’s is always inclusive, which refers to both the speaker and the addressee(s), while let us is commonly exclusive, referring to the speaker and others but not the addressee(s).
- Let’s go, we are late. - inclusive we
- Release us and let us go! - exclusive we
Negation of let's is let's not in standard English.
- Let’s not talk about it.
Don't is also used, but it is often considered non-standard.
- Let’s don’t talk about it. (US)
- Don’t let’s talk about it. (British)
Tag questions with let's typically take shall we?.
- Let's go to the beach, shall we?
- let, don’t let’s, let’s, let’s don’t, let’s not, The Columbia Guide to Standard American English, Kenneth G. Wilson, 1993.
- American English and British English, Concise Oxford Companion to the English Language, Tom McArthur, 1998.