Mandaly, after constructing a sentence in Kreyol "Enben, ou pa ka achte yon jilet aswe a.", I find out that I was not supposed to include "yon" in this sentence. By including "yon", does this not sound like good Kreyol? Or, does this not matter? Mesi anpil.

It sounds correct with "...yon jilèt ..."
Actually, you can write it with or without "yon".
Whether you have "yon" or not, it will refer to a nonspecific "jilèt"... as opposed to "jilèt la"

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