Language learning mainly encompasses the association of symbols and sounds with meaningful concepts and allows us to describe the external environment and our internal thoughts. As sleep is clearly involved in consolidation processes underlying the formation, strengthening and integration of associations (see above), it appears quite obvious that sleep may play a fundamental role in language learning. In support for this notion, numerous findings provide evidence for the beneficial influence of sleep on establishing the ‘‘mental lexicon”, particularly with respect to word learning. For example, sleep has been proven to