There is a big dilemma whether the mother tongue of the arab learners is the standard arabic or the dialectic arabic. What do you think?

i believe the mother tongue of arab learners is the standard arabic because the wods they learn to use when they are young are simple and easy to handle

This is very common problem in any language. Usually one version of a particular language is official and another is informal.

So, in the mass media, or, News channels usually the official one will be used and while people are exchanging in a very familiar and informal environment like friends talking to friends, it will be the mainstream dialect  of a particular region.