I've only heard very few people pronounce Akhal-Teke and they've said "Ah-kahl Tea-Key" but after finding a video regarding my boy's breeder and his sire Mamuk, CNN pronounces them Ahkal Take-a. So I've been going with that!
Interestingly, in the video they spell it "Akhal teka" like they're saying it - I wonder if they simply say/spell it differently in Russia, or if they're spelling it phonetically?
I know a couple who endurance race on their Akhal Teke's and they pronounce it like "teak" with no emphasis on the E at the end. Wikipedia lists it as being sounded like "teak" or "teh-key". I've never heard it pronounced with the A sound before.