I want to help some non-English-speaking acquaintances communicate better in English. Are there any web applications I can point them to which can check English for spelling mistakes or grammar mistakes? Preferably one without too many flashing advertisements.
Have you seen http://spellcheckplus.com/
If you will also consider a paid service, I can highly recommend Wordy.
You can get an instant quote automatically, simply by pasting your text online, or uploading a document. The text is then checked for grammar, spelling, punctuation and structure by professional copy-editors.
I have used the service a few times, and I think I never had to wait for more than 30 minutes for the results.
I tried spellcheckplus.com and it is a great site! I don't think using "egregious" errors is a good way of testing. A good grammar checker should catch common errors, not necessarily egregious ones (especially if they are unlikely). For example, if you write "House green the big like I" (for "I like the big greeen house"), and then expect a grammar checker to help, that is not realistic. It should catch things like "there house" and "I would have went" though, which is the case with spellcheckplus.com
It can also be used online at polishmywriting.com.
When you try Terry's example of "there house" it suggests that you may have meant "their house" and will also give you an explanation:
You may have used one word when you meant another. A common cause of these errors are homophones. A homophone is two words that sound alike but have different meanings and spellings. Review the definition of the word you used and the word suggested.
- their: something that belongs to them
- there: not here
This service also isn't cluttered with advertisements like many other services.