lang attribute not being set in HTML tag

Hi there.
The lang attribute is not being set in the HTML tag at the top of pages.  I have my language set to "en-CA" under settings.  If I use the Twenty Twenty-Three theme, my pages start with `<html lang="en-CA" prefix="og: http://ogp.me/ns#">` as expected.  When I switch back to cold box, my pages start with `<html >`.
Thanks,
Jith.
