I tried running Kokoro on my iPhone XS (several years old), and it was slower than real-time. So, i wouldn’t expect it to be usable on a Kindle. But if you find a solution, please let me know.

Kokoro can be hacked a bit (see script https://github.com/DavidVentura/translator-rs/blob/master/sc... ) which makes it about 3x faster.

My phone went from slightly slower than realtime to very comfortable (also lower latency on first utterance!)