Reading and Writing
The spoken form of language is what most children learn at home, but most societies require the skills of reading and writing for them to progress in life. Formal education is often a part of their learning environment, but some children are given instruction at home. In either case, it is important for the child to become familiar with the formal language encompassed by the rules of grammar. Here is where they truly learn to communicate through language.
Spoken language tends to drift away from its root form, and dialects or slang can be introduced. When people move and have new experiences, they may adapt their words to help them express unexpected concepts. Small children and even adults can forget the formal words they learned as slang comes into popular usage, so the value of reading and writing can help them retain the original meaning of everyday words.
The beauty of the written word, in any language, is that it does not change. When a person writes a sentence on paper, it is the same every time it is seen. This gives students a foundation to build their language skills on in any tongue, and they will be able to learn them as a comprehensive set of rules. Writing takes more effort than speaking, and words tend to retain their original meaning.
Almost every language has its own formal rules of grammar, syntax and vocabulary. When students are taught their language, they are expected to learn and understand the formal aspect. Speaking at home or with friends is when they use informal language, and it may or may not follow the formal rules. Reading as well as writing is a way to reinforce the formal rules of any language, and it helps students and adults retain that knowledge in their normal environment.