ESP8266Audio
Arduino library to play MOD, WAV, FLAC, MIDI, RTTTL, MP3
...ESP8266 is fully supported and most mature, but ESP32 is also mostly there with built-in DAC as well as external ones. For real-time, autonomous speech synthesis, check out ESP8266SAM, a library that uses this one and a port of an ancient format-based synthesis program to allow your ESP8266 to talk with low memory and no network required. All this code is released under the GPL, and all of it is to be used at your own risk. If you find any bugs, please let me know via the GitHub issue tracker or drop me an email. The MOD and MP3 routines were taken from StellaPlayer and libMAD respectively. The software I2S delta-sigma 32x oversampling DAC was my own creation and sounds quite good if I do say so myself.