Besides Funkwhale, I’m not sure there is anything else at the moment (someone please correct me if I’m wrong)
There are radios on Funkwhale, but these are just a random playlist of songs from a set list (like “Piano radio” for example)
Peertube has a livestreaming function that could be used as a radio closer to the actual sense of the word (with someone animating it), but it would take a lot of effort and I haven’t found any radio channels on Peertube. If you have a great idea, go for it and it might take off! 🎉
Here in france, everyone says “3w”. Pronouncing it entirely sounds like “Double V, double V, double V” so “3w” sounds like “Trois double V”, which funnily enough, is still longer than world wide web!