I agree with the comment above. The K definitely seems out of place, and it is somewhat hard to pronounce. Thella looks a lot better and is way easier to pronounce. Just an idea...
I have a great-great aunt with this name (although I'm not positive this is how she spelled it) and everyone in the family pronounces it "TEHK-la". Then again they're from Wisconsin so who knows!
Interesting name. Not sure I'd actually use this spelling. How would anglophones actually say this? Thek-lah? tek-lah? teek-lah? theek-lah? I like teek-lah, but the others aren't very lyrical to me.