Speech and language pathologists talk about language in terms of understanding and expression. The ability to engage with language for understanding involves being able to gain meaning from what other people are saying. Using language for expression involves being able to use words to talk about thoughts and ideas, to interact socially with others, and for literacy development.
Language has form, use and structure, so when we're learning to use language there is a lot to learn. It is a very complex process. Despite this, the ability to communicate using language comes naturally to most people. Our brains are wired to learn to talk. For many of us it is effortless. However, some children don't acquire language skills effortlessly.
Children may experience language delay or a language disorder, meaning that their language skills are not developing normally. The earlier these difficulties are identified, the better. It is the speech-language pathologist’s area to assess whether or not a child is developing typically: whether there is a delay or whether there is language impairment. If language difficulties are identified, therapy sessions aimed at helping the child to develop their skills may be recommended.
The ability to use oral language is an important foundation skill for learning to write. If thoughts and ideas cannot be organised for talking it is hard to write the simplest story. As a consequence, it is common for children with language difficulties to have difficulty with literacy skills, and vice-versa.