Which turns **on** precisely the existence of dialectal differences in pronunciation


#1

Note the Shibboleth story in Judges 12, which turns on precisely the existence of dialectal differences in pronunciation.
(A Basic Introduction to Biblical Hebrew, page 3)
In the above sentence, is the word “on” an adverb or a preposition?


#2

It is a preposition. The verb is ‘turn on’ and is a so-called phrasal verb. , It is similar in meaning to ‘to be based on’.