Although some information on very early language development during the first two years of life already exists, there are still many open questions. Detailed knowledge on typical early language development is important to fully understand the language development process.

Due to very high variation in typical early language development, early identification of language problems is sometimes challenging. The language development process may also differ in different populations (e.g. prematurely born / bilingual children). Information on early language development in different populations is needed in order to be able to treat different groups of children in the best way in the clinical context.

It is still open to question how language capacity is built up, i.e. how different language domains (e.g. lexicon, phonology, morphology, syntax) are associating with each other during the childhood years. Recent findings have proposed that there exists continuity in language development process. However, it is still open to question which features of early language development have the strongest predictive value for later language development.

During the last ten to fifteen years, knowledge on how to measure very early language development has increased. There is, however, a need for new methods which could be used effectively and economically to measure early language development in the clinical context. New measures are needed to assess the language development at pre-school age.