it's how people from Michigan or Minnesota pronounce important. They really can't help it. Someone from Michigan might come up with the lame excuse of it being a 'Michigander thing' Truth is it sounds funny and makes for good comedic relief. It's often always a good idea to ask someone from Michigan to pronounce Important for you or any word for that matter.
A: what's the latest on the super collider?
Mr. Pinecone: blah blah blah..........for 10 minutes
A: that sounds really empor-ent
A:what's so funny?