Theres been an argument spanning 13 years on this matter on one of the Jaguar forums that I frequent, here's a summary: is it BURR WALNUT or BURL WALNUT ?
Really!!!

Why on earth would people care that much?
Eventually, according to Wikapedia - BURR is correct English/European terminology, and BURL is usual USA/Canadian terminology.
But you should also trust the Cambridge dictionary more than Wikipedia UK
https://dictionary.cambridge.org/dictionary/english/burl Canada follows British spelling and grammar, not American, though most of our anglo automobile terms come from the US, though not in Quebec of course. BTW, Grouping Canadians with Americans is a a semi-slight to the former, sort of like calling a Scot and Englishman. For gomog, I try to use for British terms and spelling out of respect for where the car was made. I shall use "burr" from now on, term I grew up with from January days at -30C.
But however you spell it, burl/burr is merely a term for deformed wood, walnut merely being only one of them. I wish we saw more of the
other burl woods . Our interiors would be much more varied and individual.
BTW, I speak three languages, all badly, and I can get by in more languages even more poorly. As long as we can communicate, I am fine with whatever you wish.
L. (who comes from a land of many woods)