Why is Putonghua called Mandarin?..
Mandarin and Putonghua(PTH for short) are totally different, Mandarin contains 8 different varieties, even my mother tongue is Mandarin, it's Southwestern Mandarin, which is a little bit different from PTH, especially in phonetics(only a little bit different), and tones(I think this is quite different), vocabulary, we have many local words that PTH doesn't own..and the grammars are the same...
Well...many non-Chinese are learning Mandarin, but eventually it turns out that they're only learning PTH...
So I am curious why Putonghua is called Mandarin..?