Valid question IMHO. For instance in German software companies it seems to be fairly common to write code comments and documentation in English (even mostly communicate in English so that employees from other countries don't feel lost), while when I spent a few weeks working in China I noticed that comments and documentation are written in Chinese and communication in English isn't easy (spoken communication, written works quite well). Now I do indeed wonder if this is common for other Far East countries like South Korea and Japan too.
In a lot of the modern startups that's definitely the case, as a contractor I've come across some questionable "Denglisch" codebases a few times though.
