Regalo, Spanish for “gift,” comes from the Old French galer (“to rejoice; make merry”), with a re- prefix added for emphasis.
From the same root we get the the English gala, as well as gallant.
It makes sense: a gala is a big, merry, ball after all. Gallant is a bit more subtle: it meant, in old French, courteous — but earlier, it had originally meant, “amusing, entertaining,” from which we can see a clear relationship to making merry.
So it is noteworthy, therefore, that, good manners (being courteous) originally began as… being fun.
And all share the same g-l root to make the connection clear.