partly? what is the other part please elaborate.
and btw let's not start analyzing sentences it is not wise, you might find someone who could find grammatical mistakes on your sentence too.
In your rush to take offense you overlook my point.
No native speaker would be capable of making such basic errors as forgetting the plural "s" on "schools" and "speakers" or including the extraneous "of" in "word of native".
Do those errors adversely affect your ability to function and communicate in English? No, they don't.
Do they indicate that you would have a lesser capacity to notice and correct similar errors from students? Yes, they do.
In a labor market where there is an abundance of native speaking applicants, those seemingly trivial errors are enough to make the difference between being hired or not being hired. If you have either a written or an oral interview for an English teaching position and you consistently make such basic errors, thinking them unimportant, then you automatically lose the job. It doesn't matter what
you think or what
I think about how important such small errors are to being able to communicate. What matters is what the businessmen making the hiring decision thinks. Very few places are going to hire someone who consistently makes all the same careless errors the businessmen is hiring someone to correct in students. Imagine you owned a car detailing business and were interviewing two applicants for a job. One guy comes in a clean car and one guy comes in a nasty car. Which one would you hire?
If you haven't been able to get hired for an English teaching position in Japan it is almost certainly due to a decades-long careless inattention to what you consider trivial points of English language usage and not due to what sort of accent you have or don't have. You have to get past the gatekeeper...the person who makes the hiring decision... and he judges based on
his standards, not
yours.
To the ears of a native speaker, what may seem to you like tiny and unnoticeable omissions are actually quite jarring and impossible
not to notice. In daily life, they don't affect communication and nobody will be so rude as to correct you, but you may be certain people notice each and every one of them. If you want to be hired as an English teacher in a market where you have to compete with people who
don't make those errors and where that matters to employers then your only choice is to be more careful and avoid making those errors yourself. You have to adjust yourself to the labor market because the labor market isn't going to adjust itself to you.