Hawkerladdie, are (or were) your Scots past tenses formed in -it even when the verbal root ended in a voiced sound (or for that matter, do you have final voiced consonants in Scots at all? Of course you do, though maybe not final voiced stops). I ask because in terms of pronunciation, the English past tenses "looked" and "barked" end in "-t", not "-ed". (But the tense suffix usually written as "-ed", though pronounced "-t" in the just cited examples, is pronounced "-d" after verbs ending in vowels or consonants other than "d, t", such as "shampooed", "lagged" or "banned", and as "-ĭd" [the ĭ may be a schwa or a short e, depending on phonetic environment, idiolect, and rapidity of speech] after verbs ending in voiced stops or in "t", e.g. "banded" or "bunted". Bear in mind that when I say "verbs ending in such and such" I am referring to their final sound, not their final letter. English spelling being what it is, 'twere madness to base linguistic principles on orthographic prescriptions.

Rowan, I think I misled you into thinking in my dialect "Avenue" and "Ave Maria" have the same initial vowel. No, "Avenue" starts with pretty much the same vowel as "bad" (and "have"), but there are dialects I've heard of, mainly British but occasionally North American, where "have" has a vowel more like the Polynesian "mana" than like "manna [from heaven]"; more like "Ma. Pa." than like "Ma'am. Pam". Unfortunately, your efforts to clarify the initial vowels in "marry merry Mary" simply extends the problem to other examples. In my dialect, "airy" rhymes with "fairy", and "fairy" and "ferry" are as like as two phonological peas in a pod. When I hear you (i.e. someone who distinguishes these vowels) speak I register the difference as "their accent" but have no difficulty understanding it. You, on the other hand, might completely misunderstand an utterance in my dialect on account of the same difference. So "mutual intelligibility" of dialects (even among educated speakers of standard English dialects*) is not necessarily an equally wide street in both directions. I have the advantage in listening comprehension, but you have the advantage in avoidance of ambiguity.

Haruo

*using "standard English" in a broad sense that includes versions from Oxford and the BBC to Stanford and the ANU, and using "dialects" in the non-judgmental, scientific-linguistic sense in which all of us speak in dialects... (Remember the old adage, not true but truthful, "a language is a dialect with an army"...)