Interesting. According to Brent Spiner (the actor who plays the android Data in Star Trek: The Next Generation)
1) it was Patrick Stewart's UK pronunciation of his character's name (day-tah instead of the US's dah-tah) that made this pronunciation canon, and
2) the character of Data and the popularity of Star Trek has led to "day-tah" now being the common pronunciation in the US, too.
https://youtu.be/xeqTMTOxid8 (π min)
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