It's about 400nm Tashkent to Urgench, almost wholly over uninhabited desert. In an An-24 you were probably halfway there or more by the time you finally spoke to the captain an hour into the flight, so continuing to planned destination sounds appropriate, especially as he already had contact with them, to arrange an ambulance on arrival.
German was a common second language in Soviet schools, due to the links with the GDR (and it being a lingua franca in adjacent countries), but fewer links with English-speaking countries. Putin did German at school.