I pronounce it like
Adelaide with an A at the end. I don't think there's any correct pronunciation for it. They EYE-da pr. might be the Spanish pr. but in the US there is no reason to use that pronunciation and most people would pronounce it with an AY-da ending. I mean we don't pronounce
Hannah,
Sarah or
Nicole the original way so I don't see why I couldn't use an English pronunciation of
Adelaida.