English is the prime example of the effects of this, with it's French/Germanic split (French from the Norman aristocracy).
Of course that also to a large extent spread via the upper classes first and foremost..
There's a saying I first heard about Danish - a bastardisation of a quote often misattributed to Charles V - about how aristocrats would read Latin in books or use it at court, speak French to the ladies, German to his dog, and would only speak Danish to servants.
The exact set of languages (and animals...) differ in different versions of the saying, but generally it puts Spanish, Italian or Latin at the "top", then French, German and sometimes finally a local language.
In french there is a common pattern where words lost an "s" while a vowel gained a circumflex. i.e. hospital -> hôpital, forest -> forêt, etc. I'm guessing hostel -> hôtel is another example of that pattern.