Morrowind had voice acting for lines like detecting you and greetings when you got close, plus a few lines in story, most notably Dagoth Ur and Vivec.

For the majority of the story there was none while oblivion had like 11 people voice the entire thing and poorly. The voice acting of Oblivion was also accompanied by the way worse writing. I grew up on Baldur’s Gate 1 and 2 and later Morrowind and those were only partially voice acted and I definitely liked that as a kid as well, at least more than I did Oblivion.