@scy I can believe that day-tah became more entrenched in the US in the wake of TNG, but it's misleading to say that day-tah was the UK pronunciation and dah-tah was the US pronunciation. Day-tah was definitely in use in the US pre-TNG, and my memory is that it was already the more common pronunciation.

Here are some examples of Americans saying day-tah in the 1980s. https://www.youtube.com/watch?v=w_mm0blGMqw
https://www.youtube.com/watch?v=WAZAsn5BfSo