Why does language have the properties they have? The goal of my presentation is to provide evidence for the idea that some of the design features of language (Hocket, 1956) has emerged (partly) due to children's tendency to shape communication systems into "language-like" ones. I will discuss two design features related linguistic forms. First, language segments and linearises information. For example, when the event of "a ball rolls down the hill" is verbally described, the holistic event is encoded in a linear sequence of six words, each one of which segments out a particular aspect of the event. Second, language uses a set of discrete (as opposed to continuous) forms as building blocks for words. For example, voiced and voiceless consonants (e.g., /b/ vs. /p/) are two discrete categories along a physical continuum. Third, language can be realised in both spoken and signed format. I will present evidence that children spontaneously introduce these design features into their communication system. The evidence comes from three sources: (1) Nicaraguan Sign language, which is a new language created by a group of deaf children without any linguistic input from adults, (2) Pantomiming (gesturing without speech) by hearing English-speaking children who were asked to gesturally express certain events without any speech, (3) "Home Signs", gestural communication system developed by a deaf child growing up a in a hearing family, who have virtually no linguistic input. I will conclude that design features of language related linguistic forms are universal because all languages are learned by children, who shape language just in that way.