Praat is an application with which phoneticians can analyze, synthesize, and manipulate speech and create high-quality pictures for their articles and doctoral theses.

The source code may be downloaded here.

What’s new in this version:

Version 5.0.0.8:
Corrected the minus sign (\-m = “?”).
Version 5.0.0.7:
Object IDs are visible in editor windows.
Version 5.0.0.6:

Corrected a bug that caused Find again in the TextGrid window not to work.
Made Praat work correctly on 10.3 computers with missing fonts

Website
Download Praat