In a recent email exchange about a lost check, he ended his note by saying, very nicely:
Anyway I am sorry for any incontinence caused to you by that.
Now, in an email to his editor, that is of course nothing more than cause for a smile (and a blog post), but in academic writing—and any writing intended for an audience, for that matter—such mistakes can be the difference between acceptance and mockery.
Anyone can make this type of error (see YouTube video), but ESL writers are particularly susceptible because their vocabulary is not as expansive or solid. It is always a good idea to have someone with a firm grasp on the language review your writing to check for errors such as these.