Theres no way a Mexican can be two white people's child. Not believable and really bad casting in my opinion.
Lorelei Linklater is not a "Mexican." She was born in Mexico while her parents (both white Texans) were working there. She does cultivate an "exotic" look. Linklater is of Scottish-English ancestry and his partner of mixed Irish and European antecedents, looks to me like she might have some Greek or Italian in her background.
Lorelei's younger twin sisters appear in the later scene in the movie where there's a graduation party for Mason. They are represented as Mason's cousins. They look strikingly like Lorelei, though both have lighter brown hair.

I agree with you. This was one of the main things that annoyed me about this movie. Theres no way a Mexican can be two white people's child. Not believable and really bad casting in my opinion.

I don't care about her appearance. I can suspend my disbelief unless the SCRIPT gives me reason to doubt (and not what I know about her background, outside of the film).
She was good as a kid, less interesting as she grew up - but then, the same could be said of the boy, also.
"Your mother puts license plates in your underwear? How do you sit?!"

There was nothing wrong with her performance at all.
The night beckons, like a finger curling and uncurling as if to say "Hey, come here."

I grew up in Houston and I don't have a Texas Accent. Most of my friends don't either. It's much more prevalent in the rural areas.

I didn't realize until I read your post that that was Linkletter's daughter, but you're absolutely correct. She didn't look like she could be Mason sister is all

Nepotism is one of numerous Hollywood vices that are generally given a free pass. She was all right, but here's betting many others would have been better.
My people skills are fine. It's my tolerance of morons that needs work.

Really disagree with OPI thought she was fantastic

However, I agree she didn't look the part and she turned out not to be a very good actress either, but then, neither did Ellar to be honest. Oddly, both children were very convincing and natural when younger. As teens they brought a genuine teen ennui to the roles yet still managed to make even that seem less like good fodder for "acting" and more like poor performance.
The thing is, a lot of teenagers act that way these days. They mumble their words and don't like to converse with adults. For me, both kids did an adequate job, and their awkwardness actually adds to the realism of the film.
Linklater is a really bright guy, I think he knew what he was doing in casting his daughter. Her having darker skin is pretty much irrelevant, as far as I'm concerned. I've seen sets of siblings that look incredibly different from one another.

heard (I think it was possibly an interview with Linklater?) that Lorelei wanted to drop out halfway through and Richard had to reeeally beg her to stay part of the project. So maybe it was childhood enthusiasm at first that petered into general disinterest and to compromise, Linklater reduced her significance down a bit as they aged so she wouldn't need to be on screen as much
Linklater has mentioned several times (in different interviews) that Lorelei at one point wanted to drop out, and asked if her character could be killed off. However, he said he didn't have to do any real persuasion, because she wanted to buy a new iPhone and realized the SAG daily rate was way more than she would earn at Burger King, so she started bugging him, When will we be filming again? I need the money!
Lorelei herself says, however, that though she wanted to drop out at that particular time, she was glad she didn't and afterwards really enjoyed it and looked forward to the filming every year. She has made another film since, though she says she is not sure whether she wants to pursue acting or visual arts. She says she hated watching the film and seeing herself growing up onscreen; apparently, Linklater didn't let the kids see any of the film until it was completed.
I thought both Lorelei and Ellar did a good job with their roles. What many posters have complained about (that they seem to act badly as they get into their teens) is IMO a reflection of the fact that they portray the less attractive aspects of teens quite adeptly. Patricia Arquette says that Lorelei, in real life, is
very
different from Samantha not at all bratty and snarky. Ellar was not like Mason either, Linklater says, but as the years went by more of Ellar was incorporated into the character (his interest in photography, for example).
Here are some short interviews with Lorelei:
http://www.cinephiled.com/interview-lorelei-linklater-grows-fathers-boyhood/
http://www.texasstandard.org/shows/012315/why-lorelei-linklater-has-a-problem-with-boyhood/
http://www.dazeddigital.com/artsandculture/article/20708/1/boyhood-was-painful-to-watch-for-lorelei-linklater
http://thewildmagazine.com/blog/growing-up-with-boyhoods-lorelei-linklater/
http://www.cosmopolitan.com/entertainment/movies/q-and-a/a28312/richard-and-lorelei-linklater-boyhood-interview/

I heard (I think it was possibly an interview with Linklater?) that Lorelei wanted to drop out halfway through and Richard had to reeeally beg her to stay part of the project. So maybe it was childhood enthusiasm at first that petered into general disinterest and to compromise, Linklater reduced her significance down a bit as they aged so she wouldn't need to be on screen as much (not unlike how a sibling might generally vanish as the kids gain independence, I suppose, especially as teenagers).
I didn't find her appearance to be much of a problem. She may not have looked much like her parents but she looked like a very convincing sister for Mason. You do see some families with unexpectedly varying levels of skin tone and that often goes down to genes that come from way down the line.
Interesting that I've seen critics say 'it's a good thing Ellar remained a good actor' because he was downright terrible in some of the later scenes. A particularly badly acted one was the scene where he was splitting up with his girlfriend, IMO. I thought he was pretty good in most of his teen years but as he started to reach adulthood it all went downhill.

Your last sentence probably explains what was going on there, in my opinion. I think it must have been quite hard to find actors and actresses who could fully commit to being one of the major roles who of necessity really had to be there in key scenes throughout, for the entire 12 years.
Really the only child actors who remained constants were Ellar, the lead as Mason Jr, and Lorelei as his sister, and I guess it was hard enough for Linklater to find a set of parents who were willing to commit their child to something that took place every year for the next 12 years.
So that's one child actor contract, down, one to go and it was just easier all around to draft in one's own child. No new set of parents to negotiate with.
However, I agree she didn't look the part and she turned out not to be a very good actress either, but then, neither did Ellar to be honest. Oddly, both children were very convincing and natural when younger. As teens they brought a genuine teen ennui to the roles yet still managed to make even that seem less like good fodder for "acting" and more like poor performance.

As Samantha transitioned into a teen (when she started wearing braces) she quickly became one of the worst actresses I ever laid my eyes on. She looked incredibly forced, wooden and it was like she was reading the script. I don't blame her though. We all become a bit awkward as teenagers. She was a much better actress as a kid, surprisingly. With that being said, she kinda improved as she hit her late teen years (towards the end of the movie).
Yeah, she did look out of place in the family. Her parents and brother were fair skinned with blue eyes. Maybe Linklater couldn't find anyone else to do that part? Remember, she had to be committed to the role for 12 years

Thought she was good.
The brother/sister relationship was one of the best things in the movie. So darn realistic. There wasn't a single suggestion of sentimentality between them.

Lol! Good one.

That's because you are small-minded and easily distracted. For the record, Luke Skywalker looked nothing like his father.

I agree. She looked very out of place. The first time I saw the movie, I kept thinking there was going to be a scene where they said Ethan Hawke wasn't her biological dad.

Its called subtle acting

I think she also got bored of the movie and didn't want to do it anymore. While I do agree she looked out of place as the daughter I didn't think she did a terrible job.
Love your profile pic.
RIP Eric

She is outright exceptional in this scene:

Overall, Lorelei did an acceptable job. She was very good as a child, but, as others have noted, her lack of training as an actor showed more as the film wore on.
In a strange way, her lack of acting ability as a teen and young adult actually played into the realism of the film. I think this is what Linklater, the filmmaker was going for. I don't think he cast his 8 year old daughter strictly out of nepotism. He deserves more credit than that.
I related to the actors in the way I would relate to characters in a documentary. In that sense, Lorelei Linklater's awkwardness as an adolescent was authentic, in a way that a trained child actor wouldn't have been.
I loved her performance.
I'll take Punctuality

Yeah, I agree the sound I heard from most young Austinites when I lived there was more like a Southern California or even more specifically what used to be called "Valley girl" speak, even.
I think cultural stuff like LA valley girlisms spread easily across the nation with TV and radio, and of course later the internet.

I grew up in Austin as a child in the 1970's and teen in the 1980's in the suburbs. The youngsters that had Texas accents usually lived in south Austin or attended southern Baptist churches. The older generations born before the 1960's had the accents.
But most of us had that Southern California type of speech, or rather, what most white suburban kids in America regardless of location speak

Thanks for your informative response to my original post. Although I've been to Arizona and New Mexico, I have never visited Texas. So, I guess I was expecting the "Howdy, y'all" stereotypical speech patterns.