Earlier quoted context omitted.
BTW, just to point out a common and incorrect generalization you made in this very comment: "Yet, the two USA states share the same language (at least on official level)" No, they don't. At the federal level, there is no official language. At the state level, English is an official language of California, however it is not an official language of Louisiana. See the table at http://en.wikipedia.org/wiki/English-only_m…
From Wikipedia: "According to the 2000 census, among persons five years old and older,[78] 90.8% of Louisiana residents speak only English (99% total speak English)." Ok, it might not be "official". Only "de facto".
Also, for California, the number is only 58%. "As of 2005, 58% of California residents age five and older spoke English as a first language at home".
So they are still very different.