The world's languages differ substantially from each other. Yet, all children learn the language(s) they are born into quite easily. A major scientific question in language has been to what extent follows a universal trajectory based on an innate design for language, and to what extent it is shaped by specific properties of the language that is being learned. By comparing the acquisition of a spoken language with a language that uses a visuo-spatial format, namely signed languages, a unique window of opportunity is created for investigating this fundamental question. Compared to spoken languages, signed languages represent spatial relations in an analogue way rather than arbitrarily. The proposed study will use a novel approach to investigate whether these differences influence the trajectory of how deaf versus hearing children learn to express spatial relations in their native languages (i.e., Turkish Sign Language versus Turkish). Spatial language development of deaf children will be compared with spoken language development as well as to the co-speech gestures of hearing children as the first time. Thus the proposed study will bring together state-of-the-art research in language acquisition, sign language, and gesture studies in a unique and ground-breaking way. Furthermore gathering data on acquisition of less studied and typologically different signed and spoken languages is critical to test some of previous research results based on Western languages. Due to spread use of cochlear implants fewer deaf children learn sign languages in European countries. The context in Turkey provides an unprecedented opportunity to conduct such a study with many participants before cochlear implants are also widespread in Turkey.