Is this sentence correct?
Yesterday, you made very few grammar mistakes while talking, almost any.

Question

Answer

Not really. 
I believe you meant "Yesterday, you made very few grammar mistakes while talking, if any."
or "Yesterday, you made very few grammar mistakes while talking, almost none."
Hope this helps!

Answer

Yesterday, you made very few grammar mistakes while talking, HARDLY any.
Yesterday, you made very few grammar mistakes while talking, almost NONE.

Both of these essentially translate as "casi ningún error" in this case.

Answer

Almost correct! Just change one word.
I think you mean to say:
Yesterday, you made very few grammar mistakes while talking, almost none.

Answer

Accidentally posted here instead  of in the answers. Moving my comment....

Đừng bỏ lỡ cơ hội học ngoại ngữ ngay tại nhà. Hãy xem danh sách các gia sư ngôn ngữ giàu kinh nghiệm của chúng tôi và đăng ký buổi học đầu tiên ngay hôm nay!