I believe it used to be when I was a kid(1950's) before LA/SoCal developed thier own "culture" (surf, valleygirl, etc) because it wasn't really an accent and so movies, TV newscasters, etc adopted that "accent" as standard American speak because it was neutral. Over the years it may well be distinguishable now, and many Spanish words/idioms/phrases are incorporated into day-to-day speech