I managed to fix this by going to System Preferences > Language & Region. I changed the default language from English (UK) to English (Canada) and quit System Preferences. I then changed the default back to English (UK) and then quit System Preferences again. I then restarted macOS.
I have absolutely no idea why that works. From the number of similar posts on the internet proposing different solutions, I suspect there are multiple possible issues leading to the same problem. However, this it worked for me on macOS Big Sur 11.0.1. Unfortunately I can't find the link describing this solution to give credit but if anyone does find it do link in.
Hope this helps you.