Try identifying the stress patterns of words. Welsh usually stresses the last but one syllable of a word hence AberYSTwyth or LLanDUDno. Try stressing English place names like that BirmINGham or ManCHESTer. Doesn't work because most English words stress first syllable or second if there's a prefix. This is getting boring but I think once you realise the stress pattern of language it gets easier. Above all don't let your friend give up. If she has a nice voice she should carry on singing. It doesn't matter if things something goes wrong. Music is to enjoy.