[Lingtyp] Loanwords tend to have more uncommon phonemes?

[Joo, Ian]

Dear all,

I would like to know if there are any sources that demonstrate that loanwords tend to have a larger number of rare, uncommon sounds as opposed to native words.
My intuition tells me that this is true, but I’ve yet to find any source that makes a general typological claim on this.
I would greatly appreciate your help.

From Jena,
Ian