Once again I have been bailed up by someone who felt strongly about the slovenly way in which Australians pronounce their vowels. The word immersion should have a good clear vowel at the start but so often, even on the ABC (shock, horror!), you hear an [uh] sound.
I tried to explain about the fondness of Australian English for the indeterminate vowel sound, the 'schwa', in unstressed syllables. Perhaps a way of convincing such complainants would be to record their speech and play it back to them, pointing out all the schwas that occur in normal and natural speech. I do sometimes attempt to demonstrate this myself. First I say immersion (or whatever the word is) with the exaggerated vowels and then I put it in a sentence. 'Oh' I say with surprise, 'I just did that myself! Dropped into the indeterminate vowel. We all do it, you know, and our speech would sound very strange and unnatural if we didn't.'
But they are never convinced. There is a faint tinge of holier-than-thou-ness in it, but I think it is more a case of a school lesson learned well and entirely misdirected. It is a teacherly thing to do, to produce the exaggerated form of a word as a mnemonic to spelling. Unfortunately, it is taken as an instruction on the proper way to say the word.