Whoa, hold your horses here folks - mi and fi are variants, not mutated forms… So you’ll hear both ‘i mi’ and ‘i fi’, depending only on personal taste…
Well now you’ve just gone and ruined it…! Just as I thought I was learning something new and exciting, you’ve taken the wind out of my sails… taken the rug out from under my feet… wee weed on my bonfire. Meanie.
I think that’s turning into a point of etymology now - the important point to note here for SSiW learners is that in terms of usage, mi/fi is about personal taste, rather than rules of mutation…
Yes, that’s the point. The variation between mi and fi - whatever its etymological origin - is not dictated by mutation triggers like most mutated forms are. If it were, then nobody would say i mi - but squillions do, both in the Land of Gog and of course also back on Phobos, moon of Mars and distant homeplanet of the Gogs.
‘I can’ = dw i’n medru (North Welsh)
dw i’n gallu (South)
Then add one infinitive verb, and bung in the oven…
Result: Dw i’n medru (or gallu) cerdded = I can walk.