Clarification needed:
Hover what, Anywhere on the widget? or just a specific area on the widget.
The !PlaySound command does that quite easily:
!PlaySound=file.wav
Note, !PlaySound only supports files in PCM, and other uncompressed Wave files. (Support for WavPak, may be) So, if you want to play sound in any other format, you need to convert them to Wave files.
Another suggestion, keep the sounds within a second! users won't appreciate long files for UI input gestures like mouse hovers (Just stated a line from our UX team...

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