Learn Italian: Abbiamo molti concorrenti, ma non ne parliamo mai. - We have many competitors, but we never talk about them.

Yes! It is the present participle of the verb concorrere (to compete). In Italian, present participles usually end in -ante or -ente. While they can act as adjectives, here it acts as a noun meaning "competing people" or "competitors". The plural form changes -ente to -enti.

Why is the pronoun ne used here instead of li (them)?

The phrase relies on the verb parlare di (to talk about). Whenever you want to replace a phrase that starts with di + [someone/something], you must use the pronoun ne. Here, ne replaces di loro (about them).

Why are there two negatives (non and mai) if the English translation only says "never"?

In Italian, when a negative word like mai (never) goes after the verb, you must put non before the verb to complete the structure. This double negative is required. non ne parliamo mai is the standard way to say "we never talk about them."

Could I put ne somewhere else in the sentence?