I think Icelandic or Swahili (Swahilic?) accents are pretty hot. So far as languages, French is actually sort of ugly-sounding to me (my dad liked to yell at me in French as a kid so that might be the root lmao), but Spanish, Hindi, Japanese and the Scandinavian languages are nice to listen to. (The least sexy language/dialect I can think of is probably Quebecan French. Hhhgh.)