ISO-639A is a Ruby gem that provides the ISO 639-2 and ISO 639-1 data sets along with some convenience methods for accessing different entries and entry fields. The data comes from the LOC ISO 639-2 UTF-8 data set. The ISO 639-1 specification uses a two-letter code to identify a language and is often the recommended way to identify languages in computer applications. The ISO 639-1 specification covers most developed and widely used languages. The ISO 639-2 (Wikipedia) specification uses a three-letter code, is used primarily in bibliography and terminology and covers many more languages than the ISO 639-1 specification.