"The boats were in Stornoway yesterday."
Translation:Bha na bàtaichean ann an Steòrnabhagh an-dè.
It’s am before labial sounds (p, b, m, f), an otherwise. Compare to how in English in- changes to im- in impossible (not
inpossible) for example (but in English f never was bilabial and thus it has n- before, eg. in infrequent, but in Gaelic n- also changes to m- before f).