Only Law Can Prevent Extinction — LessWrong

Comment by Elliot Temple - Most linguists are descriptivists. There's a common misconception that descriptivists don't believe in wrong answers. Actually, they scientifically observe real communities and describe their use of language. Each of those communities has rules (often unwritten and inexplicit) for what is correct or incorrect. Children commonly make incorrect but understandable statements and are corrected. Descriptivism says every English dialect is valid instead of privileging some communities over others. Written English is a somewhat different matter. Punctuation isn't spoken and its rules aren't reducible to aspects of spoken English.

Sources:

 * What Descriptivism Is and Isn’t ("Even the most anti-prescriptivist linguist still believes in rules")
 * Why Descriptivists Are Usage Liberals ("[descriptivists] make observations about what the language is rather than state opinions about how we’d like it to be." and "But no matter how many times we insist that “descriptivism isn’t ‘anything goes’”, people continue to believe that we’re all grammatical anarchists and linguistic relativists, declaring everything correct and saying that there’s no such thing as a grammatical error.")
 * Descriptivism isn’t “anything goes” (Says "I goed to the store" is incorrect.)
 * Stephen Dodson of languagehat commenting on "The New Yorker vs. the descriptivist specter" by Ben Zimmer ("descriptivism in the linguistic sense has nothing to do with spelling or style (in the "do commas go inside or outside quotes?" sense); those things are arbitrary/conventional and are decided by reference to dictionaries and style guides, respectively. [...] That issue has nothing to do with grammar and spoken usage, which is what descriptivism addresses, and it's a disservice to clear thinking and honest discussion to pretend it does.")
 * The Linguistics of Punctuation (Argues that punctuation is its own system, not a derivative system corresponding to intonation or pauses.)
 * The Cambridge Grammar of the English