Tolkien’s dwarvish (not dwarfish) names

Confusticate and bebother these dwarves: Bilbo tries to keep names like Fili, Kili, Oin, Gloin, Bifur and Bofur straight.

For all that Tolkien devoted The Silmarillion to the vast history of the Elves (and, to a lesser extent, Men), it’s clear from The Hobbit (and in the characterization of Gimli in The Lord of the Rings) that he had a soft spot for Dwarves.

In the first place, Thorin Oakenshield isn’t the leader of a band of three or seven or even nine dwarves, but thirteen; and, remarkably, they all have personalities and relationships and are pretty well fleshed out for secondary characters.

But where did Tolkien find such distinctive dwarvish names as Fili, Kili, Dwalin, Oin, Bifur, Bofur and Bombur, among others?