Is this a think piece or a fan theory? I don't think so. I'm certainly not arguing the correctness of my reading. I'm just kind of sharing how I read it, based on where I am in my life. It fits well enough that I'm surprised that I can't find anyone else saying it, though.
This will, of course, include spoilers. For the record, I'd rather live in a world where people assumed that about posts like this.
As a parent to an Autistic child, I read Logan as a story about parenting an Autistic child.
There are some obvious reasons to suggest Laura could be Autistic, including her temper. I suppose discussing that directly, at least by the moviemakers, could create a lot of the controversies from the Autistic community that arose with The Accountant, although I'm failing to see those articles now. If someone knows one, please feel free to link it in the comments. I understand that there are good reasons why Autism advocates are concerned about the focus on issues such as that in portrayals of Autism.
For me, temper issues were a defining issue of my childhood, so I have a strong empathy for their portrayal.
Since the movie itself is about Logan, the perspective I'm really concerned with here is his, though.
When Logan first meets Laura, she does not speak at all. While there is, at first, some lack of clarity about how much she understands, aside from through psychic communication with Professor X, it becomes clear that she understands most, if not all, of what has been said to and around her. Even after the reveal that she can speak, though, she speaks in short sentences, and mostly in Spanish, so they are not always clear to Logan what she is talking about.
In the end, when she does speak a longer piece, it is a speech from Shane that she's seen earlier with Professor X. This whole bit has been referred to as too on the nose in most reviews, even very enthusiastic reviews, I've read of Logan. I think it plays differently if one takes Laura as Autistic, though. It's Echolalia.
Yes, there are plenty of other explanations for all of this, starting, of course, with a simple direct textual reading. This one worked for me, though, and gave a movie I already found moving even more resonance for me.