A couple is always 2 in American English. No matter how it is used - "couple" refers to 2. For the most part, "a few" usually means from 3 to 6 or 7 (roughly). More than that, one might use the word "several".

The only time when 'a couple' means exactly two is when it's a noun referring to two people in a relationship. If you say 'There's a nice couple living next door', this means, for example, a husband and wife, or boyfriend and girlfriend. In most other cases, the number is less precise. The quantitive expression 'a couple of' means 'a few' - usually two or three. For example, we'd say 'a couple of days ago', if we can't remember whether something happened the day before yesterday, or the day before that.

Its same as in your language. Couple can mean two or it can mean few. It is ambiguous and not meant to be taken literally.

There is indeed ambiguous meaning in the word 'couple'. I would take it carefully when I'm using it. Thank you, Vince

I would always interpret 'a couple of' as being two. If I wanted a small (unspecified) number of items then I would ask for 'a few of'.