me, te, se, nous, vous, se

The use of the apostrophe before a verb like in "s'assoit" is called a "pronominal verb" or a reflexive verb. 

In French, reflexive verbs indicate that the subject of the verb is also the object. 

They are constructed with a reflexive pronoun (me, te, se, nous, vous, se) that agrees with the subject, followed by the conjugated verb.

In this case, "s'assoit" is the reflexive form of the verb "asseoir" (to sit). 

The reflexive pronoun "se" indicates that the subject is performing the action on itself, so "s'assoit" translates to "he/she sits down" or "he/she is sitting down."

Here's how it breaks down:

"s'" is the reflexive pronoun meaning "himself," "herself," or "itself" (in this case, it's "himself" or "herself").

"assoit" is the conjugated form of the verb "asseoir" in the present tense, third person singular, matching the subject.

So, "s'assoit" literally means "he/she sits down" or "he/she is sitting down."

Reflexive verbs are used when the subject of the verb is also the object of the verb's action. 

They are common in many languages, including French, Spanish, and Italian.