Sorry, y'all are off base. Standard American accent is from the Midwest. We might not have as distinct an accent here on the West Coast as, say, Boston, or one of the Carolinas, but we have our own twang and speech patterns.
I barely understood a word of that link, but what I got from it was that Californian and MidWestern is largely the same, except for minor conditions (pin vs pen?), of which I'm not sure who it meant said what in what way. And if I translated correctly, it's suggesting that Californian is closer to the dictionary than General American (TBH, I don't really understand anything it's saying, other than maybe the vowel merger bits on certain word combos).
Also, if you are a Californian (like me) like you're contextual information suggests, then I hereby revoke your California card for using y'all. 