I have been not curious as kids. I have never asked why we say not Qinghua but Tsinghua, Maotai but Moutai. I just remember them as new English words, treating them as a kind of special Pinyin.

Recently, I got a term called ”Wade-Giles”, which “was the general system of transcription in the English-speaking world for most of the 20th century, used in several standard reference books and in all books about China published in western countries before 1979...” (wikipedia) Many of words based on this system also are popular today, even though Pinyin is more and more prevailing on the translation of certain locations or names in mandarin. For example, Sun Yat-sen, Chunghwa,Tsingdao. What caught my eyes in a paper is that Huawei has a same spelling according to pinyin and Wade-Giles, which is an advantage in its development of making the brand well-known at home and abroad.

Above all, I just sigh there are plenty of vocabularies need to be remembered, which is really painful in most cases. 

reading more:威妥玛式拼音法

                             http://www.pinyin.info/romanization/wadegiles/