I'm sorry but "Bell" is not the nickname from "Bernard" XD (maybe this is due to the pronunciation in Japanese)
It's "beru" in Japanese i guess
In Japanese Bernard would be transcribed as "Berunarudo", So the nickname in Japanese is actually "Beru". Japanese doesn't have 'L' nor does it have single consonants apart from 'N'.
I'm sorry but "Bell" is not the nickname from "Bernard" XD (maybe this is due to the pronunciation in Japanese)