Previously identified goof states that young Morrie translates the telegram from the hospital into German, and that this is incorrect since the father is Russian. However, young Morrie is translating into Yiddish, not German, which would have been the language used by Russian Jewish immigrants.
Mitch is supposedly a talented pianist who gave up a promising career in music, yet in the recording studio when the producer asks for an F# Mitch plays an F.