This doesn't seem to work - not even if I hardcode the locale argument of the formatter to some specific language.

Looking at the source of Android's DateUtil, there are a lot of hardcoded occurences of "Locale.getDefault()", without a way to override that behavior: http://androidxref.com/4.4.2_r2/xref/frameworks/base/core/java/android/text/format/DateUtils.java