Calibre 7.18 introduces a neural network-based text-to-speech feature called Piper, operating locally. It also debuts an experimental PDF conversion engine, supports word-by-word tracking during read-aloud sessions, and includes various minor enhancements and bug fixes.
https://alternativeto.net/news/2024/9/calibre-7-18-released-with-local-text-to-speech-enhanced-pdf-conversion-and-more/