Update README.md

Corrected format to formant.

README.md

@@ -3,7 +3,7 @@ Arduino library for parsing and decoding MOD, WAV, MP3, FLAC, MIDI, AAC, and RTT
 
 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](https://github.com/earlephilhower/ESP8266SAM), a library which 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.
+For real-time, autonomous speech synthesis, check out [ESP8266SAM](https://github.com/earlephilhower/ESP8266SAM), a library which uses this one and a port of an ancient formant-based synthesis program to allow your ESP8266 to talk with low memory and no network required.
 
 ## Disclaimer
 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.