...and yet the first thing I switch off in every tool is the spellchecker, because they get utterly confused with the mix of English, German and my local dialect that I'm using when communicating with different people. I'd say doing a spellchecker "right" is apparently still a major feat of software engineering ;)
I wish it just struggled with the mix of multiple languages, it can't even handle my native one. A plural compound word in translative case with a clitic? I can only dream about it, it can't even do all the cases reliably.
I guess what I'm wondering is how obscure it has to get (or perhaps how low the GDP of the people speaking a language has to be) before custom spell checking rules aren't considered worth it to bigcorps anymore. Though I'm also kinda interested in what this weird language thing is you're talking about.