Dialogue vs Dialog on "What is Human Computer Interaction?" Article

Hello! I noticed that in the Figma article What is Human Computer Interaction?, the author writes:

Dialogue. Use clear and concise language to communicate task completion, like  “Purchase Confirmed” pop-ups after completing an online order.

On Shneiderman’s website, he writes: 

Design dialogs to yield closure.
Sequences of actions should be organized into groups with a beginning, middle, and end. Informative feedback at the completion of a group of actions gives users the satisfaction of accomplishment, a sense of relief, a signal to drop contingency plans from their minds, and an indicator to prepare for the next group of actions. For example, e-commerce websites move users from selecting products to the checkout, ending with a clear confirmation page that completes the transaction.

I understand that they are variations of the same word but I would argue that in this context, it is important to use dialog because Schneiderman is referring to the importance of the graphical interface  (like a dialog box) and the clear completion of an interaction. The clarity is in making sure your users are clearly starting and ending an interaction.

Dialog is to provide users with a clear signal of task completion, like moving users to a clear confirmation page after clicking Complete Purchase when completing an online order. 

Also, I was in a lecture for my HCI masters two years ago (at UMD where Schneiderman taught and founded the Human-Computer Interaction Lab) where the professor used Figma’s definition in her presentation explaining Schneiderman’s rules and when she got to “Dialogue”, she told the class “Yeah, dialogue , like, make sure you are communicating using clear and concise language like you are having a dialogue”.

And this has bothered me ever since.