Previous research has suggested that shy children have difficulties with language. Now, a new longitudinal study paints a more nuanced picture. The study, of 816 toddlers, found that children who are inhibited in their behavior tend to speak less but understand what's being said as well as less shy peers. In other words, these children have performance problems when speaking with others, but don't lack capability, suggesting that they're merely reluctant to respond rather than delayed or deficient in understanding language.

The study, conducted at the University of Colorado Boulder and the University of Connecticut, appears in the journal Child Development.

"Our findings suggest that inhibited behaviors like shyness don't hamper language acquisition overall but instead relate specifically to how toddlers express themselves through words," according to Ashley K. Smith Watts, graduate student, and Soo H. Rhee, associate professor of psychology, both of the University of Colorado, who were part of the research team.

The study also found that girls had higher levels of both shyness and language than boys. However, the degree to which shyness was related to language development was similar for girls and boys.

Researchers collected information from 816 children in Colorado who were primarily White but varied in socioeconomic status and who were representative of the population of Boulder. Information was collected at ages 14, 20, and 24 months through parent reports and by observing children during home and lab visits. The researchers assessed expressive, or spoken, language by asking children to imitate certain sounds and words (like /ai/ and "mama"), and by asking the children to answer questions verbally. They assessed receptive, or understood, language by asking children to follow instructions ("Give me the cup and ball").

"Shy children may need help with developing their speaking abilities," added Smith Watts and Rhee. "They may benefit from interventions that target confidence, social competence, and autonomy to support the development of expressive language. For example, caregivers can encourage them to be autonomous and arrange play dates with compatible peers."