Hello Kailas and thank you for writing to JustAsk!
In my opinion, there are a few things you can do to enrich a child's vocabulary.
1-READ with your child. As you read books or magazines with your child, try to discuss the story using synonyms and idioms. For example, if the author wrote the sentence, "The bunny ran very fast" you could rephrase the sentence and say that "The rabbit scurried". This simple technique introduces synonyms and alternate expressions. Another example would be if the author wrote, "It rained like cats and dogs" you could discuss what is really meant by this phrase/idiom. Then give words that would describe this statement, such as "storming".
2-Another way to improve vocabulary is to play board games such as SCRABBLE or BOGGLE. You can introduce new words during this fun and relaxing game time together.
3-Lastly, try to read the closed captions on television for children's programming. Although there are sometimes unintentional errors with closed captioning, it is overall a great method to help improve language skills including vocabulary.
Good luck and thanks again for writing to JustAsk!
Read, read, read. That's pretty much it. When you see a word you don't know, you look it up and memorize it. Having dealt with the word in context, in real use, will make retention easier.
But I'm just getting ready to write an article on this topic, and there's another technique that I'm going to emphasize. This works for any age.
Never teach or learn individual words. Teach clusters. Rhyming words. Words from French. Words that lawyers use. Food or menu words. Music words. Car words. Learn 5 or 10 words at a time. Each word is a mnemonic for the others.
Did you know there are 333 common words directly imported from Latin? Pure Latin, pure English. Each one tells a big story going back 2000+ years. See link to my "Latin Lives On."