I assumed that Gboard spell checker contacted servers constantly and have it switched off for whatever good that does. I recently tried enabling it to play with other options and noticed that it works when my phone is entirely offline.
Does anyone know if it works locally or does it just send a bunch of data out once I give it internet access again?
Bonus question: Does anyone know of a privacy respecting spell checker for android? It looks like Florisboard can work with Hunspell through Nuspell but not on Android. Is that right?
The spellchecker by default does (as part of some initiative regarding improving spellcheck or whatever). There is a setting to disable it and another setting to disable telemetry. Disabling both of these effectively makes the keyboard offline apart from things like Stickers and Emojikitchen.
You can also block internet access to GBoard and it'll work just fine.
If you don't hard-depend on GBoard, you may wanna look into Florisboard and Helium314's OpenBoard Fork