[LostInBayport]

My guess ‘Chartaya’ is pronounced SHART-tay-a.

I hope her friends don't call her Shart as a nickname. It has an entirely different meaning!

[HiTech RedNeck]

oh boy, I googled it. what has been read cannot be unread.

[Calvin Locke]

I had to go to the urban dictionary after that.

While her actions point to the soft "Ch", imho, I'd recommend her adopting the hard "Ch", if at all possible.

She seems like the type to hang with those familiar with urban slang, rather than the OED crowd.