The Is-Is Phenomenon (IIP), unnoticed until the mid 1980's, but now very common, is the repeated use of "is" (or occasionally "was") for no good reason. Still relatively rare in writing, it is annoyingly common in speech. Here is an invented example:
One subject, two verbs, no sense. (For real-life examples, watch an hour of interviews on television.)
One possible explanation of the origin of the IIP is thoughtless extrapolation from the following legitimate construction:
The question is, is he literate?
Two subjects, two verbs, no problem.
For a depressing indication of how popular this form has become, try a Web search for a string like "fact is is that", and observe how small a fraction of the results are complaints about this usage.