> Most of the hispanics whose families arrived in California before the English speakers arrived have long since become native English speakers.

That's true of most Californios, sure, but they are, by far, a minority of California Hispanics, who are mostly from families that immigrated much more recently.

If you had read my comment past the first sentence, you would see that the second addressed your the larger population too.

Even if they are immigrants, knowing Spanish makes them half-way native English speakers because of the similarities between English and Spanish.

English is a Germanic language, with vocab borrowed from lots of other sources but mostly French, Spanish is a Romance language (with, especially in it's Latin American form) a bunch of vocabulary borrowed from Nahuatl and Quechua. They are extremely dissimilar grammatically, and though they have some overlap and similarities in vocabulary, it's nowhere close to making fluency with either making you even minimally functional (much less halfway native) in the other.

This chart shows approximate linguistic distances between most European languages. It looks pretty accurate; in my experience Dutch speakers do indeed have an easier time learning English compared to native speakers of other languages.

http://bigthink.com/strange-maps/a-map-of-lexical-distances-...

There are enough similarities to give them significant advantages compared to immigrants coming from other parts of the language tree. English and Spanish have thousands of cognates. Having almost exactly the same alphabet is also a huge advantage. Having already learned thousands of permutations of the same alphabet letters (words) will make memorizing and learning the next thousand permutations much easier.

> There are enough similarities to give them significant advantages compared to immigrants coming from other parts of the language tree.

Depends which other parts. Disadvantaged compared to German or Dutch speakers, and even French speakers, but, sure, advantages compared to other, say, people whose only prior language is Mandarin. And, of course, a big disadvantage compared to immigrants who already speak English, even if it's not American English.

But still very far from starting off even functional, much less halfway to native fluency.

> but, sure, advantages compared to other, say, people whose only prior language is Mandarin

I wouldn't understate the significant advantages.

> And, of course, a big disadvantage compared to immigrants who already speak English, even if it's not American English.

Not necessarily. A large percentage of children of immigrants speak with their family (nuclear and extended) mostly in their native language even if their parents can speak decent English. The English skills don't transfer much unless the parents are very active in their child's English education.

Among immigrants and their languages, Spanish is about as close to English as you can get, though. Not a lot of German/Swedish/Dutch immigration going on to California.