Sometimes when not working on my own machines at a client the locale is set to a language other than English and some Java frameworks such as Hibernate then will dutifully print out error messages in that language.
This is next to useless. At a time when you still had nothing but a printed manual in your local language to go on this might have made some sense but nowadays people research error messages on the internet. Searching for some arcane ORM framework error message in a language other than English is a futile endeavour.