When I was at school learning German, there were several german language hits in NZ, Falco with Der Kommissar, Trio with Da Da Da and Nena with 99 Luftballon. 99 Luftballon came out as single, with side A the German version which ws the one in the charts and played on the TV music show and side B an English translation. Both sides were sung in a “german accent” (Platdeutsch, = lowland or kind of common or lower class German at that). The words however were significantly different and had been massively changed to suit the music.
A few years later Falco had several other hits, this time in English and with a midatlantic accent (e.g Kowboyz and Indianz, Kiss of Kathleen Turner). d’ugh