Icelandic language
The First Grammatical Treatise is of great interest to the history of linguistics, since it systematically used the technique of minimal pairs to establish the inventory of distinctive sounds or phonemes in the Icelandic language, in a manner reminiscent of the methods of structural linguistics. It is also notable for revealing the existence of a whole series of nasal vowel phonemes, whose presence in the Icelandic language of the time would otherwise be unknown.