 who speaks the language which is theThe First Grammatical Treatiseis a 12th-century work on its phonology
First Grammatical Treatise: The First Grammatical Treatise (Icelandic: "Fyrsta málfræðiritgerðin" ) is a 12th-century work on the phonology of the Old Norse or Old Icelandic language. Old Norse: Old Norse was a North Germanic language that was spoken by inhabitants of Scandinavia and inhabitants of their overseas settlements during about the 9th to 13th centuries.
inhabitants of Scandinavia