London, Sep 17 (IANS): Children generally produce words at 10 to 15 months and the range of vocabulary expands as they grow. However, according to a study, the key to learning to talk lies in the genes.

Researchers have found evidence that genetic factors may contribute to the development of language during infancy.

"We found the genetic link during the ages 15 to 18 months when toddlers typically communicate with single words only before their linguistic skills advance to two-word combinations and more complex grammatical structures," said Dr Beate St. Pourcain who jointly led the research with professor Davey Smith at the MRC Integrative Epidemiology Unit, University of Bristol.

The team discovered a significant link between genetic changes near the ROBO2 gene and the number of words spoken by children in the early stages of language development.

The ROBO2 gene contains the instructions for making the ROBO2 protein. This protein directs chemicals in brain cells and other neuronal cell formations that may help infants to develop language but also to produce sounds.

The ROBO2 protein also closely interacts with other ROBO proteins that have previously been linked to problems with reading and the storage of speech sounds, the study noted.

"The research helps us better understand the genetic factors which may be involved in the early language development in healthy children, particularly at a time when children speak with single words only," professor Smith stressed.

The study was carried out by an international team of scientists from the Early Genetics and Lifecourse Epidemiology Consortium (EAGLE) and involved data from over 10,000 children.

The results appeared in the journal Nature Communications.