It actually does... but not to any one of them. It uses bits from different conventions, since no single convention is a good fit (none have all the required s

It actually does... but not to any one of them. It uses bits from different conventions, since no single convention is a good fit (none have all the required sounds). Besides, they all disagree with each other anyway. Q is from Albanian, for example. R is from Czech. Another romanization (Wade-Giles) uses J for that sound (taking it from French). Neither is a perfect match (the voiced retroflex r in Czech and the voiced fricative j in French are, ideally, not quite the same sounds) plus it can be realized in different ways by native Mandarin speakers but it's close enough. I think pinyin is bloody brilliant.