May 2017
What can I do to be able to chat with my toddler after I learn him to talk?
I have up-to-date game, I won't like to use mods...
June 2017
I believe that feature is added with the Generations Expansion. I could be wrong though,
June 2017 - last edited June 2017
^
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