Issue can also have two meanings - 1. A dispute or difficulty , or 2. A topic. For definition 1 of issues, the difference between that use of issues and problems is that problems are usually difficult circumstances that require resolving. Issues are often describing the personal disputes or encounters a person experiences. I'm not sure which context you're using the sentence you provided. "There are different opinions on the issue of learning foreign languages" This sentence is already correct if you're using the word "issue" to describe it's meaning "topic." If that is what you are trying to communicate you could say "There are different opinions on the topic of learning foreign languages." However, if the sentence you provided is describing the difficulty of learning foreign language, you would want to say: "There are different opinions regarding the problems of learning foreign languages." In this case you're describing the difficulty of learning foreign languages, and "issues" would sound too personal, problems would sound better. Since you're declaring a fact, using the word "problems" would sound more objective and sounds better in this case. I hope that makes sense!

"Issue" is not necessarily negative, is more like a topic. "There are different opinions on the issue of learning foreign languages" is right, but it could be rewritten as "There are different opinions regarding learning foreign languages". "Problem" generally infers something bad.

I would add that here in the US the word 'issue' started creeping into workplace lingo about 20 years ago. It was seen as a way to sound soft. 'Troubles' oddly enough is seen as very negative and defeatist in American work and personal dialogue. Why this came to be is a mystery to me. In my mind, troubles and issues are two distinct things.

A problem is always bad, an "issue" is sometimes negative but sometimes it isn't. Your sentence is correct by the way. All problems are issues, but not all issues are problems.