Somehow, spell checking is considered as a process for single words. But there are lots of word fixed and very common word groups for which spellcheck could be useful when done using mutliple ‘tokens’.
I suggested a method like this several times, but unfortunately, it was not picked up by anyone (no problem; there is so much to do around grammar…)
But I will give it a try myself in the time to come. Not in Java, not in LanguageTool, since I never mastered the (at least for me) complex ecosystem of LT.
I will try this for English, since most of the people here understand that. When I manage to get a prototype running (webserver, PHP) I will get back to you for you to check it out. Not only will it report possible errors and maybe suggestions, but it will also ask for feedback, so the software might learn.
It is rather ambitious, but: no guts, no glory.