You should be talking to them all the time saying words and telling them everything you are doing with them. They should be saying up to 10 or more words by 18 months but understand everything you say to them. Also correct them if they mispronounce the words, and you should not talk baby talk to them. Get the potty chair out this month and let them sit on the potty while you are sitting on yours. Teach them the words for it like pee pee or poo poo, but I have only seen 3 babies potty trained before 18 months old.
Most babies are two years old or more.
But go ahead and introduce it to them but do not expect them to go on the potty until later. They are throwing temper tantrums by now and it gets worse by 2 years old. They are pretty well behaved by 4 years old but terrible twos starts at 9 months. You should punish no-nos, but do not punish temper tantrums. Walk away and laugh at them.