i've gotten a few reports in now where the messages were not in english because the user was setting LC_ALL to their language. our docs/wiki have long discouraged this behavior in favor of LANG and specific LC_xxx vars. we should add a check to emerge so that when it sees LC_ALL set it issues a warning that they should be setting LANG only and refer them to the wiki: https://wiki.gentoo.org/wiki/Localization/Guide