Ordering a drink from Starbucks can be quite the task. Shiv put together this helpful PDF file to help you out in the process.
BTW: I typically order a [personal] to go no-fat [no water] extra hot grande tazo chia latte, but since its getting warmer I think I'll switch to a [personal] to go grande chocolate malt, which evidently is easier to say.
Mind you, until I read this PDF, I didn't think of ordering extra shots of chia... things could get interesting :)