In the south, there entered people from Africa on whose influence on the language nobody would have been a penny, but they dug into this alien tongue with their own inheritance, and the combined language delivered - a common tongue for them and an uncommon fresh word-hoard for English.

 on whose  소유격 관계대명사 앞에 전치사 on 이 여기서 어떤역할을 하나요~~??