Question Author
Thanks, SH, for recognising what I was getting at and the film suggestion. I haven't actually seen it but tried to get a flavour of its sounds via Youtube. Sadly to little avail.
Are you suggesting, Dr B, that - with the possible exception of 'mirror' - the examples I give are pretty close to New York and Boston speech? Presumably, that's what any imitator would be striving for, after all.
Yes, II_b, that seems to confirm a conceivable Boston connection. I never heard President Kennedy saying 'mirror', but it somehow seems likely that he said it along such lines. Maybe my whole query IS partly at least about Boston Irish.
Thanks, C, you seem to confirm the above. To be honest, though, I find the sounds I refer attractive rather than lazy. Accordingly, if I ever do hit the shores of the US of A, it seems I'd better head for Massachusetts/New York or Louisiana/Mississippi.
Thanks to all of you.