Charles, thank you, but I am apparently not understanding something. The macro appears to work, but after closing and reopening the template, it has reverted to US English.

Since the online dotx is a copy of one I made locally, I opened the local one first to create the change, planning to then upload and replace the old one. When the above-cited problem occurred with the former, I tried making a dotm and installing the macro in This Document instead of Module 1, since the latter is based in the Normal template, but the same thing occurred. (I barely know my way around macros, and am no coder; please forgive any gaffs here.) Meanwhile, I discovered that, for whatever reason, a new docx opened normally from Word (from default Normal) has retained the English (Canada) choice. Well, at least it stuck somewhere, but that has to be changed back.

What results from the macro is, Canada appears above United States, both checked at the top of the proofing language dialogue box, with Canada highlighted. After saving, closing, and reopening, Canada remains at the top, but United States is highlighted. I presume this means that both spellings are acceptable, but Word starts looking for US or something?

I need more guidance, please. If I have not provided adequate information, please let me know.
Thank you.