The pPolyglots

When you say "the polyglots," it sounds as if you're referring to a specific group of polyglots. Just "polyglots" is more general.

TheHow do polyglots... How do they not forget so manythe languages they've learned?

Is it hard for them to use so many different languages regularly?

If you think it's easy to practice one or two languages, I think it's easy enough.

But if you learn five or more languages?. are a lot to juggle.

I get what you're trying to say but it's an unfinished thought and feels awkward.

The polyglots... Hhow do they not forget so many languages?

Is it hard for them to use different languages regularly?

Your original sentence isn't wrong, but it makes more sense to add a word like "different". This shows that these people are speaking more than one language.

But if you learn five or more languages?...

You might want to add one more sentence at the end of this one, in order to clearly express what you're thinking. This is optional, and the sentence makes sense as it is! One note: in English, when we use multiple periods, we usually use them in groups of three, like "...". This punctuation is called an ellipsis if you didn't know