G'day Tex,
kunix is referring to finding those references in the GW firmware and of it reading regions 11 & 13 to verify they start with AUDIMG or AUDPKG [which they also do in the case of StreetPilot 26xx on which these GW navi units are based]. Region Dumps 11 & 13 from SP2610 pics:

SP2610 Rgns11 13 Dump

If you'd like to look at the audio package used to update the Voices for SP26xx, it's available here:
Code:
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Firmware from here:
Code:
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Hex dumps for regions 11 & 13 from SP2610 in case you'd like to examine them further:
Spoiler: Click
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