I'll preface this comment by noting that I'm not posting this to try and attack you or anything, I get that English isn't your first language and I'd much rather that you keep putting out quality gameplay (
) than worry too much about your grammar. I just think the question is interesting.
The thing about language is that it isn't just a way of communicating, it's a way of expressing yourself. Fundamentally, "No one has time to do that" and "Ain't nobody got time for that!" communicate the same thing, but a person reading them they come across as two different characters with completely different backgrounds. The way characters express themselves reveals a lot about the character, not just their grammar but the words they choose to use. We were just discussing Tamiko for instance, if you took out the images and everything you knew about the character, you could still guess that Tamiko doesn't know English very well since she always refers to herself and others by name instead of pronouns ("I", "you", "s/he") and uses small words exclusively.
To me, the biggest downside of the writer being less skilled at English grammar is that it's difficult to tell when a particular word, grammar mistake or turn of phrase is something intended to be a part of the character, or is just there. I noticed this a lot with Sada this update, in that because of the way her grammar reads like someone who speaks English as a second language (and the character model, I suppose), I couldn't help but read her lines in a Japanese accent.
I'm not sure what your first language is, but imagine how a person learning it as a second language speaks. Now imagine if a book you liked was written entirely in that manner of speaking. It would be difficult to differentiate the characters, since they all speak the same way.
As I said at first, I'm not trying to attack you personally or the game. I like the game, I wouldn't bother with this thread if I didn't. I just thought the question was interesting and felt like responding to it.
