In english there only a few deterministic words: "the, thoses, these..."

In french there is a lot more.

Ex:

I eat the banana / I eat bananas

Je mange la banane / Je mange des bananes

We don't hear the s at the end but the word "des" specify it's plural verbally.

It can also be "je mange les bananes"

Using "des" is to talk about some random bananas. Using "les" is to talk about specific bananas in the context of the conversation