Gytha "Nanny" Ogg

So i'm playing Nanny Ogg in my schools production and i was wondering what type of accent i should learn for her? I was also wandering if anyone had any tips on how to play her?
Thank You :)

The Anhk Morpork game on I-pad has her with a broad (I think) Southern England accent.

I am no expert on accents but it is the sort which actors use to portray yokels.

She's not a townie, she's a country woman, with the knowledge and knowhow that comes from living in a rural environment. I don't see her as academically clever, but she'd no fool. I think of her as having a country accent (it's the Welsh borders in my head), but not a strong one - although strength of accent is very much in the ear of the hearer. I don't think of a local yokel when I think of her - but I'm sure she can play the local yokel when she thinks it to her advantage.

I think the accent you choose will depend on where you are. Trying a specific accent is hard enough for the professional actors. She needs sound as if she's from wherever your location would consider a local yokel to be from - and lay it on thick when she's acting up and being the sweet old lady.