Buildings do not have "yes" sounds:
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In PyDAT, I pasted the Marine entry onto a building to make the building become a normal unit. The "yes" sound then changes, but it is still greyed out & doesn't play in-game:
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Can this be changed? I am working with GPTP, Firegraft & Python Modding Suite.

In the Units.dat file structure, there are only 106 entries for the Ready, Yes, and Annoyed sounds, so you'll need to find a way to extend those fields and have the game read them. I personally don't know how you can achieve this.

Farty has been working on DatExt recently, but it's still a work in progress. I'm not sure whether expanded soundsets are implemented yet.