Re: [IE conlangs]

As a non-linguist, and especially a non-phonologist, I wonder at all the
infinitesimal distinctions that are made concerning vowel sounds. English as
spoken in London, New Jersey, Bombay, and by people with any one of a number
of different "foreign" accents are all radically different in terms of the
exact nature of the vowel sounds.  Yet each of these variations can be
easily understood by most English speakers.  Such subtle nuances of
pronunciation seem, therefore, to have exactly zero information content.
(Other than to identify the nationality of the speaker.)

English, at least, would appear to be very tolerant of variety in vowel
sounds.  Are other languages this tolerant, or are there languages in which
slight mispronunciations would confuse the meaning of a sentence?

My own pet theory is that vowels sounds are important, but only just barely.
(My own conlang, Tazhi, is set in a parallel world where it is a global
language
with many local variations in pronunciation which are all ultimately
unimportant.)

Anyway, the reason I bring all this up is that it seems to me that any
candidate for a global language must be a some language which is extremely
tolerant of various types of "mispronunciation".  How do languages other
than English stack up in this regard?

--Gary.