Longer and Yon

Longer adverb - For more time.

Yon and longer are semantically related In some cases you can use "Yon" instead an adverb "Longer".

Yon adverb - At or in an indicated (usually distant) place (`yon' is archaic and dialectal).

Longer and yon are semantically related in at a greater distance topic. You can use "Longer" instead an adverb "Yon".