Sims 3 - can't chat with toddler

I believe that feature is added with the Generations Expansion. I could be wrong though,

^

There was a bug some years ago that caused this issue to happen i don't know if there is a solution for it without the possibility of a mod  BUT we're not allowed to talk about those here as they are neither endorsed or supported by EA and are an at your own risk

but no harm in trying when you launch your game do a save as new name then go to edit town move the family out and back in and or save a copy of the family to the library start a new game and see if the chat option is available  or the resetsim cheat

Press Ctrl+Shift+C

Type ResetSim  (Sims full name)

edit to add

http://sims3.crinrict.com/en/2013/10/chat-with-for-toddlers-missing.html