ok. I'm going to pop in here because I had asked about this before:
A neighboring country is specifically french themed. 
Secondly, there is a big difference between a person knowing a language from a neighboring country vs knowing colloquialisms from half a world away. 
I think you and me, as English speakers, would be a bit surprised if I suddenly busted out my rich repository of Swahili slang terms. I mean seriously brother, do we have to bust out the bomba bomboms before things get rasmi here? Cause I just want things hamna noma man.