I mean I make more than my fair share of vowel mix-ups, wrong prepositions and extra letters when using English, but I have yet to understand why this particular problem exists. I understand the 'ie' vs 'ei' thing, as in "Stein" vs "Stien": they both are pronounced the same way in English.
What I don't get is the 'e' vs 'u' thing, as it is not like those are pronounced identically in English. Yet, even in published texts this particular thing appears frequently: as an example the Canadian Globe and Mail:
...
Schoneburg, just south of Berlin-Mitte (central Berlin), is also where Dietrich was born; a bronze plaque at Leberstrasse 65 marks the spot. Today, the fashionable neighbourhood, which has housed everyone from Albert Einstein (who, like Dietrich, left Nazi Berlin) to David Bowie (who worked with Dietrich on her last film, Just a Gigolo, in 1979), is appropriately Bohemian, with lots of stylish cafés and gay and lesbian clubs.
...http://www.theglobeandmail.com/servlet/story/RTGAM.20051011.wdietricht1012/BNStory/specialTravel/The facts are all correct, but the district is called Schöneberg, not -burg. It is a hill, =berg (mountain by north-German standards), not a castle = burg.
;-)