A new issue just started today for me. The sim voices are very quiet in Create a Sim. I have all the packs apart from Eco Lifestyle, and no mods active.
It appears to have been a hardware issue, which now seems to be rectified.
Go to Game Options, Audio. Make sure voices are set to 100%.
Voices are fine in live mode.
Do you have any Mods or CC? If so move your Mods folder to the Desktop and delete localthumbcache.package. Then test the game.
If it works now check for updates to your Mods and CC. Add it back a little at a time while testing until you have found all that are broken.
It appears to have been a hardware issue, which now seems to be rectified.
