Learn Hardcore Greek: Η ακρόαση ελληνικών με βοηθάει να μιλάω καλύτερα. - Listening to Greek helps me speak better.

So Η ακρόαση ελληνικών is literally something like the listening to Greek. Greek often uses a noun like this where English might prefer a gerund such as listening.

A more verb-like version would be Το να ακούω ελληνικά..., which is also natural.

Why does the sentence start with η? English usually just says listening, not the listening.

Greek uses the definite article much more often than English, especially with abstract nouns and general activities.

So Η ακρόαση ελληνικών sounds normal and natural in Greek, even though English would usually leave out the.

Without the article, ακρόαση ελληνικών can still appear in certain contexts, but η ακρόαση ελληνικών is the more normal full sentence form.

Why is it ελληνικών and not ελληνικά?

Because ελληνικών is in the genitive plural, and it depends on the noun ακρόαση.

The structure is basically:

ακρόαση ελληνικών = listening of Greek

This is different from a sentence with the verb ακούω:

Ακούω ελληνικά = I listen to Greek / I hear Greek

There, ελληνικά is the direct object.
Here, ελληνικών is linked to the noun ακρόαση.