They are DIFFERENT GENRES. Not only did Mozart use different languages for each, the forms are different and so is the instrumentation.
The Italian equivalent of German "lied" is "canto", not "aria".
Anyway - can the OP not simply take a photo of a distinctive phrase from the music and upload it? (If the original was a concerto, my bet is that it will turn out to be the famous 6/8 finale from the horn concerto no.4, since that should transfer to the concertina reasonably well).