Children who get good sleep at night are more likely to have good vocabulary as they can learn and retain new words better than kids who don't get enough sleep.

A new study has found that the mechanism that the adults use to learn is the same mechanism that enables children to develop vocabulary.

"These are truly exciting results which open up a new dimension of research in our understanding of language development. Our work provides the first evidence that sleep is associated with the integration of newly-learned words into the mental dictionaries of children," said Dr Anna Weighall from the psychology research group at Sheffield Hallam.

Researchers found that new words began assimilating with other words in the brain after a cycle of 12 hours. But, this process happens only if the child has slept during the period. Sleep provides an environment that helps the brain start consolidating learned material that it shifts from short-term memory to long-term memory.

"Children's ability to recall and recognise new words improved approximately 12 hours after training, but only if sleep occurs. The key effects were maintained one week later, suggesting that these new words are retained in long-term memory," said Dr Lisa Henderson from the Department of Psychology at University of York.

Children with disturbed sleep or those who snore a lot while sleeping are more likely to have problems with learning and behavior. Previous research has shown that sleep can aid in learning of a complex motor-skill.

Researchers say that further studies in the field will show how sleep affects children who are diagnosed with developmental and neurological problems like autism and dyslexia.

"Clearly, children need to learn material well in the first place, but then they also need to sleep well in order to weave these new memories in with their established knowledge. The combination of these two components is the key to robust learning," said Professor Gareth Gaskell in the Department of Psychology at University of York.

The study is published in the journal Developmental Science.