/ws/1 returns language.iso_code_3b instead of language.iso_code_3t. classic.musicbrainz.org, /ws/2 and the search server all use language.iso_code_3t, so this seems to be a mistake.

Compare
http://classic.musicbrainz.org/ws/1/release/7fcd8d50-c1fd-4753-a592-e57d978fcf19?type=xml and http://musicbrainz.org/ws/1/release/7fcd8d50-c1fd-4753-a592-e57d978fcf19?type=xml
also http://musicbrainz.org/ws/2/release/7fcd8d50-c1fd-4753-a592-e57d978fcf19