This master thesis consists of five parts. The first part emphasizes the importance of stimulative environment for speech development. Eventhough every child is born with predispositions for learning to speak, they need social interaction with its environment in order to achieve those predispositions. The second part describes child's language development. Language development starts even before child is born and lasts the whole life. The most important period for acquisition and development of speech are first three years of child's life. In preverbal period children start to understand language and its functions, while in verbal period they start to make language. Children of preschool age significantly progress in all language aspects: phonology, semantics, gramatics and pragmatics. At age of 6 and 7 children start to show interest for reading and writing of letters and numbers. That's why the third part is about early literacy. Children first master the basics of oral speech and afterwards they start with mastering the written speech. Mastering written speech means fluent and correct reading and writing. Unlike mastering speech which children learn smoothly and usually without additional teaching, learning written language requires initiation and guided activities. In order to master reading the following skills and knowledge: phonological awareness, vocabulary, narration, awareness of the written text and naming letters. Metalinguistic awareness has the key role in early literacy. This understands ones awareness of language units, awareness of relations between words, their meaning and syntax. In the last part of this thesis results of conducted research are showed. The aim of this research was to determine the level of metalinguistic awareness in preschool children. The research showed that metalinguistic awareness in early childhood just starts to develop.