This could be an interesting challenge, if I end up with a Sim who is mute! I had no problem with this with previous toddlers, one brought up with a parent with Family-Oriented trait and one (different family) with neither parent with that trait. Walking and potty training were both taught just fine.
I quit the game, restarted my computer, and tried again. Nope. Now that I think of it, the other two kids were raised before I installed Generations. Also, I made the age length of toddlers and most other life stages longer. I'll try putting those back on default and seeing if that helps.
Any other ideas? Thanks in advance!