Can two words make a sentence?

Yes, two words can make a sentence if they contain a subject and a verb.

Here are some examples:

* "Go home." (Subject: You (implied), Verb: Go)

* "Rain falls." (Subject: Rain, Verb: falls)

* "Birds fly." (Subject: Birds, Verb: fly)

However, not all two-word combinations form a sentence. For example, "Red ball" is a noun phrase, not a sentence.