By the time a child is 12 to 18 months old, they have learned quite a few words and can understand simple instructions.
But then encourage them to talk more.
If you listen to them you can grasp words they are trying to string together in short sentences, this then allows you to help them by teaching them how to say the words they want to say.
Never laugh or make fun of what there saying or how they are saying it.
Give names to all the things your child points to
They can't wait. Toddlers hate waiting and may forget what they were trying to say. If you're busy and know your child wants to talk to you, say something such as: "I'll be with you in a minute. I just have to finish this phone call."
They keep interrupting. Everything is immediate in your toddler's world. What he has to tell you is probably important to him, but if you're busy it's OK to tell him that he'll have to wait until later. If this happens often, though, you might want to think about whether your toddler is getting enough attention at other times.
They don't want to talk. Parents often say their toddlers won't tell them about their day at nursery or a visit to a friend's house. Ask open questions that don't just require a yes or no answer, and give gentle encouragement by prompting, reflecting back what he says and showing you're interested.
They never seem to stop talking. By the time they're three years old, most children are in a phase of asking endless questions. Answer as patiently as you can - your responses are helping your child learn. And appreciate this stage while it lasts: only small children think you have all the answers.
They're always whining. Don't fall into the trap of always responding to whining and give positive attention when he speaks normally.