Here are the reasons why I use all of my electronic devices in English:

• I already know English, so it’s not a burden.
• Localization is never perfect. Just dig a bit deeper into the settings in Windows, and you’ll always stumble upon some English here and there, no matter what the language setting says.
• Troubleshooting sucks if you have to use another language. There are a million posts, answers and articles about your problem written in English, but only 9 written in your local language. Among the million articles in English, you’ll also find a few that were written by people who know what they’re doing. The 9 articles and posts in the local language were all written by clueless idiots.
• With some applications, like Excel, localization really hurts usability. I guess it’s fine for people who make calculations only a few times a year, but people who use Excel on a daily basis just hate the translated function names. If you already know your way around the English functions, using a translated version means you’ve got your both hands tied behind your back. What used to be trivial, suddenly becomes an epic voyage, just like it is with those who use Excel only once a year. Good luck trying to get anything done with the translated version. It might even be be faster with a pen and paper.