Adding vs. not removing accessibility
As Jeremy Keith states in The language of accessibility, accessiblity is something that is an inherent part of Web documents that make proper use of semantic HTML.
Far from being something that is added to a site, accessibility is something we need to ensure isn't removed. From that perspective, the phrase "making a site accessible" isn't accurate.
Very well put. The only sites that need to be "made accessible" are those that are badly constructed to begin with and those that once were accessible but have had too many accessibility-removing additions grafted on.
Jeremy also notes that the German word for accessibility is "Barrierefreiheit", which means "free from obstacles". To me that perfectly describes what accessibility is about – not creating barriers that will make it difficult for people or machines to access your site's content. The Swedish word for accessibility is "tillgänglighet", which just like in English is a bit problematic since saying that a site is accessible can also be interpreted as "Yes, the server is up and running, so the site is accessible." Hardcore server-side people seem to be the most easily confused by this, probably since keeping the server running is one of their most important tasks.
To get back to the issue of making vs. keeping a site accessible, I will follow Jeremy's lead and use keeping from now on. Most of the time, anyway. In many cases sites really do need to be "made accessible".