A family of Microsoft word processing software products for creating web, email, and print documents.
Has English (Canada) been successfully set as your default for new documents? In that case, pasting content from another document in plain text format should preserve the language formatting.
For existing documents, changing the default won't make a difference. You can try to modify the language of the Normal style (which is the "parent" for most other styles in Word) but sometimes you have no other choice than to (re-)apply the correct language format after having selected all the content in a document.