I dipped into an old medieval verse epic Morte Arthur (not Malory's, another one) which called Gawain's sword "Galuthe." It's really just as well this didn't make it into the general tradition. Galuthe doesn't have the same ring as Excalibur.
"Excalibur is looking particularly shiny today, wot?" "Oh, yes yes. Lovely day for it and all that. And did you get Galoot sharpened after that tiff with Sir Pellinore?" "Your majesty, my sword's name is GALUTHE." "Ah, that's just your Northern accent!"