Stereotype or not, it's a word Canadians are famous for — two simple letters baked into the tail end of so many of our sentences. But few realize "eh" actually predates the country's creation by a century or more.
A CBC article about linguistics research on “eh” as a Canadianism (with a nice little video that unfortunately won’t embed). Excerpt:
Martina Wiltschko, a professor of linguistics at UBC who studies confirmationals at what's called the Eh Lab, said the U.S. equivalent is "huh."
"Huh," however, is only used by Americans in a way to confirm whether something is true — for example, if someone says, "Oh, you have a new dog, huh?"
What sets us apart is the use of "eh" in other contexts.
Americans would never say: "I have a new dog, huh?"
Wiltschko says that implies the person has forgotten whether or not they have a new dog.
She suggests what makes the Canadian use of "eh" unique — despite the fact it's widely used in New Zealand and the small English Channel island of Guernsey — is what she calls the narrative "eh" used during storytelling.
For example: "Then I walk into the house, 'eh'? And it is just filled with people, 'eh'?"
Each sentence is asking a question, but the speaker is not really expecting a response. It's just a vehicle to draw the storyteller's audience in.
Read the whole thing (and watch the video!)