Here we've got ideas, observations on ELT, including Mark's Pronunciation Blog and loads of conference and speaker reports...
In speaking styles, there is a continuum between mumbling and rolling your ‘r’s –. What I mean by mumbling here is speaking with as little mouth movement as possible in order to minimize effort on the part of the speaker.
A bird does not sing because it has an answer; it sings because it has a song
(China)
From As they say in Zanzibar by David Crystal
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