I'm no expert, but I studied a little linguistics in school. The standard reason given for the fact that German derived words in English seem ‘lower' than their French derived equivalents is that the French words came into the language via the Norman invasion. These French (well, a mixture of French and Viking) speaking invaders became the ruling class and their language was adopted by the aristocracy. Later, through interaction with the continent, Latin was also used as the common language of the aristocracy. When all of these influences mixed together to form what we now think of as English, the Latin and French words kept their highbrow connotations and the Anglo-Saxon words were associated with the peasantry. The textbook example is the distinction between a ‘stool' (Anglo-Saxon derived) and a ‘chair' (French derived). The real situation is probably much more complex, but it makes for good cocktail conversation. Check out these links for more:
http://en.wikipedia.org/wiki/English...age#Vocabulary
http://en.wikipedia.org/wiki/Norman_invasion
Also, Schlepp, Schmuck (which actually mean male genitalia and only means a dud as an insult), Schmutz, Kaputt, and verklemmt all came into English through Yiddish and so their meaning is twice filtered.