Language development is a process that starts early in human life, when a person begins to acquire language by learning it as it is spoken and by mimicry. Children's language development moves from simplicity to complexity. Infants start without language. Yet by four months of age, babies can read lips and discriminate speech sounds. Usually, language starts off as recall of simple words without associated meaning, but as children age, words acquire meaning, and connections between words are formed. In time, sentences start to form as words are joined together to create logical meaning. As a person gets older, new meanings and new associations are created and vocabulary increases as more words are learned. Infants use their bodies, vocal cries and other preverbal vocalisations to communicate their wants, needs and dispositions. Even though most children begin to vocalise and eventually verbalise at various ages and at different rates, they learn their first language without conscious instruction from parents or caretakers. It is a seemingly effortless task that grows increasingly difficult with age. Of course, before any learning can begin, the child must be biologically and socially mature enough. This book presents recent important research in the field from around the world.