"is" is correct here, due to the implied nouns. "Data" in this case is an appositive and serves to describe the implied noun, "word." And "plural" is an implied noun for "plural word"
You can see it most clearly if you fill in the implied nouns:
Oh fuck off with that pretentious ass pronunciation. I mean my God, just say "data" like a normal person! So tired of people trying to get all fancy with their pronunciations. Data is the only correct pronunciation. And while we're at it, it's "gif" not "gif" and "gnome" not "gnome"
I say data (dah-ta) when it is information that cannot normally be read by a human, and data (day-ta) when it is information that has been compiled about a topic that is in human readable format.
"The data on the hard drive has been corrupted." - dah-ta
"The data shows that you have a life expectancy of 78 years" -day-ta