Language acquisition is the process and learning curve of skills by which a child acquires language. This set of skills contains the ability to perceive and comprehend language, as well as the ability to produce and use words and sentences to communicate. Language acquisition normally proceeds in a predictable course that is evaluated as normal developmental milestones. The term language acquisition is normally used to refer only to a person's first language. The reason for this is that the acquisition of a first language as a child creates the most fundamental skills of language such as attaching meaning to phonemic groups, reproducing sounds to express thoughts, understanding the importance of grammar and syntax. After these basic associations and mental pathways are established additional languages can be learned without needing to establish new mental pathways.