My Excel tabs and commands are in English, yet the numbers are shown in German (0,1 instead of 0.1). I looked here (Change numbering language of the Excel context by changing the Windows language) but it doesn't resolve it. How can I switch to English?
Number notation settings use the system locale setting.
In order to set this to english, go to Control Panel > Country / Region and find the More settings... at the bottom.
There you can change the notation settings. This will change the settings for the entire system though, and there's no way around it.