All parents were told to fill in a questionnaire after monitoring their child's activities during trial.
"We found that distributing blocks was associated with significantly higher language scores in a sample of middle and low-income children," said Dimitri A. Christakis at University of Washington, who led the team of researchers.
Scientists said that the children who had received blocks had an average language assessment score 15 percent higher than the other children, reported health portal Medical News Today.
The children who play with blocks are likely to have better cognitive development -- a process by which the brain develops the abilities to think, learn and remember. It enables a child to solve problems and understand concepts, the study said.
Playing with blocks is nowadays often being replaced with other activities like watching TV that do not encourage language development, the researchers said in the latest issue of the Archives of Paediatrics and Adolescent Medicine published by American Medical Association.
Christakis however said it was a pilot project and required further study to corroborate the findings.