My best guess is that singing longer notes will reduce the effect of the accent that you have.

Lily Allen’s songs tend to be a little faster paced, as she does this little singing rap thing, her verses sound British but the choruses that she has tend to be less recognizably British. This also makes sense because accents come from the way people pronounce words (usually with a different emphasis on different parts of the word e.g. aLU-min-um vs ALU-MIN-ium), so rapping would show off the accent more than singing, which would require people emphasize sounds and elongate parts of the word based on melody and not speech patterns.

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