Klingon bird-of-prey HMS Bounty had to literally travel back to the 20th century to find humpback whales so they could speak to the alien probe threatening to destroy earth, which happened to speak whale.
The universal translator already speaks to the bottlenose dolphin crewmembers - albeit that was 80 years later - but it can't speak or understand whale?
Humpback whalesongs have been widely recorded even in the 20th century before they went extinct. It seems at least some rudimentary library of whale language should have existed as a reference.
Why did the universal translator fail to allow dialogue with the alien probe?