“…he heard Laucile say” (instead of says) can be correct?

Question

Is the following text has a mistake or is it correct?

This book say "say" about 3rd person singular, apparently instead of "says", but I'm not sure if it is a typo or it's acceptable in such kind of literature (it is a professional book) or maybe I miss here a grammar rule.

This is a phrase from a book so called "Discovering Fiction Level 1 Student's Book":

One day he overheard her talking about him with a friend. Lucile was saying:

"other men live in things and events and emotions and the future. but he seems to know that living is something else..."

What else? This friend interrupted curiously.

and he heard Laucile say: "Well, of course every one knows, really. But he lives it too.".

Answer 1

Thanks to the special verbs like 'hear, see, watch'... and so on. I have seen many such examples where the main action is done by someone else who is observing, hearing, noticing or seeing. This is quite similar to the usage of 'let him go' and not goes. Because there too, the main action is not done by the third person.

He heard Lucile say instead of says?

Because the main action (of hearing) is done by 'he.' We put 's' in a verb when the main action is done by the third person.

He comes out of a car (main action of 'coming out' is performed by him).
She saw him come out of a car (main action of 'seeing him' is performed by her).

Replacing the pronoun with a name makes no difference.

Ricky comes out of a car
Sonia saw Ricky come out of a car.