One of my favorite examples of how borrowed words get the grammatical treatment of the receiving language (more than one sputnik is sputniks < Eng. pl. –s, not Russian –i) is the singular of bartender in Swahili. Swahili is a Bantu language, bantu being the word in those languages for “persons, people”. The plural is muntu, persons or people, so ba > mu. Got it?
When the British arrived, one of the jobs they gave local people was that of bartender. Speaking a non-rhotic dialect of English, they pronounced it “bah tendah”. That was borrowed into Swahili as “batenda”, so when they hired only one, they hired – you guessed it – a mutenda.
(Note: I had originally written this with the prefixes backwards: ba = plural, mu = singular)