Rakshasa, Yuan-ti, Green Hag and some others will want to be in different forms without their voiceset giving them away. I suggest one of the following:
1) -soundset is just enabled for these hidden races so the players can adjust as they adjust shape/disguises/etc.
2) Each shape gets its own soundset saved so you can choose one and then use it as you change. e.g. Yuan-ti gets a snake one in snake form, instead of screaming battlecries when attacking.