I'm way behind on my Language Log reading, but I just noticed Wayne Leman blogging about this Mark Liberman post about an instance of the singular 'they' in the KJV. I know there are manby older instances, but this is the KJV.
This isn't new to me (see here), but one counterargument in the comments on Wayne's post is worth responding to. The anonymous commenter argues that it couldn't be a singular 'they' but must instead be some roundabout form (particular to this example and not usable in other singular 'they' examples from the same period), and the only real argument for this is that the verb seems to be plural. It's 'have', not the singular 'has' that would be expected if you had a singular subject.
There's one major problem with this. Singular 'they' (in the newer dialects of English that have it as a regular feature nowadays) does not take a 'has' but a 'have'. It's a singular 'have' as well. The following sentence clearly has a singular subject and verb in the second clause: "Someone took my pencil, and they have it on their person." So why couldn't we read 'have' in the KJV as singular, just as it is in today's English?