I find with accents if I try and imitate the sound then it can become clear the closest word form that produces that sound, if that makes sense.
This works well both in speech and sign with our 1 year old too (oh not "poo" but "boots"; {moves open hand forward and backwards away from body at chest height} oh right "lawnmower" ...).
Personally I've had to "translate" between a South African and an Ulsterman before, both of whom were speaking English but with extremely different accents.