From Audacity Manual
Customizable Keyboard Shortcuts
You can use keyboard combinations to perform many actions in Audacity; for example pressing CTRL + 1 on the keyboard zooms in a step. The combinations associated with different commands can be changed or added to on the Keyboard Preferences tab.
Mouse clicks and movements can also be used to perform some actions. The Mouse Preferences tab lists the mouse gestures which are available but these cannot be changed at the moment.
You can download and install plug-ins to add extra functionality to Audacity. Plug-ins can give you extra effects, or more audio generation and analysis capability.
- Nyquist: A number of Nyquist plug-ins are already included with Audacity which you will see in the Audacity "Plug-Ins" folder with a file name ending in ".ny". Nyquist is a dialect of LISP specially developed for audio processing. It can generate or process sound effects, or analyze audio content.
Nyquist plug-ins are text files, so it is relatively easy to modify them or even create your own Nyquist plug-ins in any text editor.
- Other plug-in formats: Other plug-in formats can be added:
Anyone can download our source code. Changing the code and recompiling Audacity allows you to change any aspect of its behavior or turn on experimental or optional features.
If you are interested in working with the Audacity codebase please consider joining our Developer Community. Your code changes can then potentially be incorporated into Audacity for the benefit of all users.