For example, here in Germany a lot of mcu-related german-language resources are written in the mikrocontroller.net wiki. It has some good content, but it's often very apparent that not much has been updated in the last ~10 years, in many cases misdirecting potential beginners to less-that-optimal progression paths.
You can also see a lot of people with programming experience switching their system to English, to easily find resources in case of e.g. obscure errors.
The language-mastery issue is real, especially for very young people, but I'm not sure if "forcing" people isn't the better call. At least in my peer group it seems like most interested people became pretty adept at English and I'm not aware of any that gave up because of language issues (although I'm sure there are many examples).
The suggestions for more simplified English in the article seem like good ideas to me. Often times the subject matter is complicated enough, even for people who don't have issues understanding the language.