Apparently there is a gap concerning the grammar checks in languagetool.
Some examples (which can be reproduced on languagetool.org) of sentences
for which no errors are found.
“There is not reason to said that it is wrong.”
“Why would we go there? Why would we go there.”
“What doe you think about this?”
“There id a big difference between them.”
“He has got 2 leg and 3 head.”
So I wondered whether this is a known issue? And are there any plans to improve the grammar checks?
Error detection rules can be created with Create a new LanguageTool rule and contributions are very welcome. We don’t have a maintainer for English, so progress is very slow unless users contribute rules. More documentation is available at Development Overview - LanguageTool Wiki.