Communication skills during social interaction at 18 months' age, such as comprehension of instructions and play behaviour, have been shown to predict the results on language tests three years later. Accordingly, children with weak communication skills are at risk for persistent problems of language and communication. Problems of communication in social interaction are also common in children with neuropsychiatric disorders, such as ADHD (attention deficit hyperactivity disorder) and ASD (autism spectrum disorder). For different reasons, it is important to identify children who are at risk for language impairment and neuropsychiatric disorders at as an early age as possible. First, early identification allows early intervention, which may increase the chances of a positive outcome for the child. Second, early identification may decrease the risk of secondary problems with behaviour, and social and emotional wellbeing, which are frequently occurring in children with neuropsychiatric disorders. This paper is an overview of the literature focusing on the importance of early communication skills, i.e. language use in a social interaction context. Conclusion: Early communication skills in social interaction are a possible predictor of language impairment and neuropsychiatric disorders, and should therefore be included in early screening procedures. Furthermore, social interaction enhances language development, and can therefore be regarded as a tool in language intervention.