This is the 36th most frequent Catalan word.
li
The Catalan word "li" is an indirect object pronoun meaning "to him," "to her," or "to it."
Here, 'li' is an indirect object pronoun referring to 'her' or 'him'. It indicates the person to whom the book was given.
Li vaig donar el llibre ahir.
I gave her/him the book yesterday.
Here, 'li' is used as an indirect object pronoun to indicate the person he speaks to.
Ell sempre li parla amb molt respecte.
He always speaks to her/him with great respect.
In this sentence, 'li' is combined with the verb 'donar' (to give) to indicate the recipient of the message.