It is very important for adults to talk and listen to children. Children will learn all their important vocabulary from the adults they spend the most time with. If you find it difficult to know what to say to your child you can use some of the techniques that teachers use in school! How about trying the following techniques?
Commentary
This is when adults:
Describe what a child is doing right now using simple repetitive phrases.
How do I do it?
Just look at what they are doing and then say what they are doing! Easy Peasy.
Can I have an example?
"You are building a tower! It is a very tall tower. It is made out of lots of colourful bricks."
Anything I shouldn't do?
Don't ask questions. Adults feel like they should ask children questions to see what they know but you don't need to when you are commenting. Commenting is all about modelling vocabulary and sentence structure. The children will learn from repetition.
Expanding
This is when adults:
Repeat what a child has said but add 1-2 words of your own
How do I do it?
Repeat what the child has said and add different types of words such as nouns, verbs or adjectives and stress those words.
Can I have an example?
Child: I went shops
Adult: You went shopping yesterday
OR
Adult: You went shopping with mummy
Anything I shouldn't do?
Don't correct the child if they say the wrong thing like "I goed to the shop". Just repeat it back but with the correct tense. "Yes, you went to the shop".