Wat does those 2 dots over letter 'a' mean? In wat cases do we have to use such 2 dots?
The two dots can be found above an a, an o or a u. They don't have any meaning of its own, they just form different letters. So an ä is simply another letter than an a and the same holds for ö and ü. In order to write correct German you have to use these letters in words that have them.
Dulingo. Not only myself but many others are complaining about the same issue. You can't understand that voice! Why don't you change it to a MALE VOICE?
Is "mögen" personal and "mag" for some one else? "Ich mögen handy" "er hag handy"?