Yawcam -> Settings -> Language
Yawcam is a multi language software and can load all text from a language file at runtime.
It is possible to change the language in two different ways:
If you choose the latter this window will popup:
The "Change..." button will open a file chooser dialog, where you can choose a language file for Yawcam. It will look something like this:
Select a file and click "Open".
The dialog disappears and the other dialog from above is visible again. Click "OK" and the language will be changed.