I hope I haven't made anyone self conscious about their writing by pointing out how I can tell the difference between a native fluency and a learned mastery of English. I sure didn't intend to.
There is a big difference between me noticing little things that clue me in, because I am trained to see these things as cultural and linguistic differences based on inadequacies of the language model a deaf child was provided, and someone reading these errors on say a job application. I realize that it is not a sign of intelligence, capability, or even level of education, and is nothing more than a developmental gap produced by the child's environment. That is why I don't even mention it most of the time, and why I asked Jiro's permission before using him as an example. Someone not familiar with the linguistic differences and the gaps produced by an oral environment would see it as a deficiency. It is also why, when assessing a child's (or adult's) language development and proficiency, we have to look beyond simply the way they speak to the very environment they were raised in or educated in. If I see these errors in one of my student's writing, the first question I ask is, "How were you educated?" If they say orally, I know that environment, and not lack of English knowlege, is responsible. I also know what is needed to remediate the problems, and that the problems will always likely be there to some extent, and therefore will recommend that a tutor be employed to read over any papers or assignments they turn it to help them correct grammar and syntax and add some creativity to their writing.