`  :Technically, a writing system is not part of the language. It is separate. Many languages do not have a writing system, and many native speakers of languages that have one don't know how to use it. In fact, writing has only been invented a very few number of times (if not just once) in the history of humanity. All others are derivatives. But the main difference here is that writing has to be invented. It is an add-on to language, and separate from the language itself. For example, a native speaker of English would never mispronounce the word ``their``, but might frequently misspell it. In a generative view of language, this is because the language is acquired naturally, whereas writing has to be taught.  `