[File:Germanic dialects ca. AD 1.png|thumb|right|300px|The distribution of the primary Germanic dialect groups in Europe in around AD 1: ]] In historical linguistics, the Ingvaeonic nasal spirant law (also called the Anglo-Frisian or North Sea Germanic nasal spirant law) is a description of a phonological development that occurred in the Ingvaeonic dialects of the West Germanic languages. This includes Old English, Old Frisian, and Old Saxon, and to a small degree Old Dutch (Old Low Franconian).