last few months its been terrible. addon not working at all. not show on any website. cant turn on or off. i need to reinstal it everyday to work for an hour. will be deleting. to bad as i had it for years

I'm very concerned about privacy with this extension. As an example of what they collect (from their privacy policy).
Usage information (such as the date and time of visits, pages viewed, links to/from any page, and time spent in a session)
Device information (such as your internet protocol (IP) address, Internet service provider, operating system, computer model, language settings and CPU details, referrer URL, time zone information, data volume transferred, access status/ HTTP status code, and web browser type).
Inference Information about your usage of LanguageTool (such as whether you are a frequent document uploader or user of a particular feature). Location information (approximated, based on your IP address).

Almost none of this has anything to do with helping to check spelling and grammar and it goes way beyond what anyone should be willing to share to any company, let alone an extension.

it does not work with Thunderbird 128.6.0

My God, this tool used to be the prime tool for spell-checking. In recent weeks, they somehow F-ed up the alorithm, and now the spell-checking is close to a retarded - constantly suggesting wrong intepretation, highlighting simple words that does not make any sense. Please update it back.

They say it works on almost any web site, just not the ones I use. I'm not sure where all of the 5-star reviews come from, but I found it uninspiring and not useful.

Not a fan of "AI" part, I just wanted a single word spelling checker, absolutely don't need any of the other features :/

Terribly clunky and giving some of the worst grammar suggestions turning my sentences into broken Engrish

I just want a good spellchecker that quickly helps fix words, not this mess

Made my performance horrible. Turning it off fixed the issue immediately.

AI

Cannot detect Romanian language, shame! Also to send all the information to your data base. No thank you and adios!

Yet more AI garbage. Go away and leave me alone forever, please and thank you.

Will record your personal info including bank info and passwords very sketchy and dangerous! Total garbage I can manage far batter than this joke of an add on. I tried it out just in case I missed something and it cost me more time trying to stop all the mistakes it made! I'd leave out a letter like say "leter" and it would give me all the choices except "LETTER"! As for so called reviews claiming the premium is great I wonder how much they were paid or do they work for the joke of a company. This is by far the worse add-on I've ever tried. It's non-stop so called mistakes aren't mistakes like " it will point it out for no reason and the user is left with a bunch of nonsense. Avoid this you'll do better on your own and will save yourself time on correcting their mistakes. As for the 5 star reviews yeah right!

You get notified of certain errors only checked by having a premium subscription, but it won't tell you where or what the errors are and you can't disable this incredibly annoying behavior. Also, despite the fact that there's no mention of AI in the description, AI integration is all over it (and very limited for free users). Even the name of the extension in the Add-On Manager has AI in it. It's the very first word! What a weird, shady-seeming, and obnoxious extension.
And by the way, LanguageTool, your setup process has at least two typos in it. You can't even be bothered to run your own copy through the AI tools you try to push on us? You failed to inspire confidence from the very beginning and then you lived up to that impression spectacularly.

Es zeigt die ganze Zeit es wären noch mehr fehler vorhanden, aber nicht wo sie sein sollen.

Per its new privacy policy, the addon now records and sends all writing back to its data centres allowing LanguageTool admins to read through.

Intrusive, overblown and constantly nagging about an upgrade many can't afford. Don't need something as complicated as this.