If you listen carefully you can hear sentences with a double "is" all the time.
President Obama does it. “The fact of the matter is is that…,” he said at the House Republican Conference on January 29, 2010.
Michigan Radio's Rina Miller talks with Anne Curzan, a professor of English at the University of Michigan, who specializes in linguistics.
“I think what’s happening here is that it happens with these focusing expressions, like the fact is, the point is, the reality is. If you think about that expression, really what we’re saying is, 'pay attention to what I’m about to say. Focus on what’s coming next, the point that I'm about to make,'” said Curzan.
But the question is, why do we get a second is?
“What I think is happening is that initial phrase the point is, the fact is, is becoming what linguists might call a lexical bundle, or a prefabricated unit, and it serves as the subject, the point is and if that’s the subject then you need a verb, is,” she said.
And Curzan says there is another double is that has long been considered grammatical in a construction like, all it is is.
“And some folks say that a construction like 'the fact is is, is ungrammatical. But for speakers who use that, it’s not a disfluency. They’re not stumbling. So, my job as a linguist it to figure out what’s going on,” she said.