In response to another question I asked, I was told spelling is not a part of language because it is a part of writing. This statement confuses me. Writing is a form of communication and is therefore, a part of written languages. Writing is directly related to spoken forms of the same language and though written langugaes can exist without a spoken form, and spoken languages exist without written versions, I don't understand how that would mean writing isn't an aspect of langage.
Specifically in regard to spelling in English, we have standardized spelling. There are British Standards as well as US standards and the two are distinct despite more commonality than difference. What spelling is "correct" is dictated by where the writer is communicating. For example, realized vs. realised which are both phonetically correct, but which "standard" is chosen for use is largely dependent on where you learn your spelling, do your reading, get published etc.
If this is not a part of "language" than what is it? Can someone please explain this distinction or separation to me? The comment had up-votes which would indicate to me that others reading the comment were not also confused by it and even agreed. I would just like to understand this perspective that is brand new to me?