If you add only "English" for Mail.app, it won't let users choose other encodings than UTF-8 and English encodings. If you want to use other encodings, you can _add_ language, for example "Japanese", to that key. (By keeping "English" first in the list, Mail.app UI will stay in English.)
Language Switcher
Language Switcher adds key "AppleLanguage" to plist in ~/Library/Preferences/(applications plist).plist file.
If you add only "English" for Mail.app, it won't let users choose other encodings than UTF-8 and English encodings. If you want to use other encodings, you can _add_ language, for example "Japanese", to that key. (By keeping "English" first in the list, Mail.app UI will stay in English.)
If you add only "English" for Mail.app, it won't let users choose other encodings than UTF-8 and English encodings. If you want to use other encodings, you can _add_ language, for example "Japanese", to that key. (By keeping "English" first in the list, Mail.app UI will stay in English.)