|Originally the North Sea coast from Friesland to Jutland|
Ingvaeonic is named after the Ingaevones, a West Germanic cultural group or proto-tribe along the North Sea coast. It is not thought of as a monolithic proto-language, but rather as a group of closely related dialects that underwent several areal changes in relative unison.
The grouping was first proposed in Nordgermanen und Alemanen (1942) by German linguist and philologist Friedrich Maurer, as an alternative to the strict tree diagrams which had become popular following the work of 19th century linguist August Schleicher and which assumed the existence of a special Anglo-Frisian group. The other groupings are Istvaeonic, from the Istvaeones, including Dutch, Afrikaans, and related languages; and Irminonic, from the Irminones, including the High German languages.
Linguistic evidence for Ingvaeonic are common innovations observed in Old Frisian, Old English and Old Saxon such as the following:
- The so-called Ingvaeonic nasal spirant law, which (e.g.) converted *munþ "mouth" into *mūþ (cf. Old English mūþ).
- The loss of the reflexive pronoun
- The reduction of the three verbal plural forms into one form ending in -þ
- The development of Class III weak verbs into a relic class consisting of four verbs (*sagjan "to say", *hugjan "to think", *habjan "to have", *libjan "to live")
- The split of the Class II weak verb ending *-ō- into *-ō-/-ōja-
- Development of a plural ending *-ōs in a-stem nouns
- Possibly, the monophthongization of *ai to ē/ā, and *au to ō/ā (this may represent independent changes in Old Saxon and Anglo-Frisian)
Several, but not all, of these characteristics are also found in Dutch. It did not generally undergo the nasal spirant law (except for a few words), it kept the three plural endings distinct, and it did not have the -s plural. But it did undergo near-full monophthongization (some instances of -ei- persisted), it did lose the reflexive pronoun (and later regained it through borrowing), and had the same four relic verbs in weak class 3.
- Nordhoff, Sebastian; Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2013). "North Sea Germanic". Glottolog. Leipzig: Max Planck Institute for Evolutionary Anthropology.
- Some include West Flemish. Cf. Bremmer (2009:22).
- For a full discussion of the areal changes involved and their relative chronologies, see Voyles (1992).
- "Friedrich Maurer (Lehrstuhl für Germanische Philologie - Linguistik)". Germanistik.uni-freiburg.de. Retrieved 2013-12-01.
- Bremmer, Rolf H. (2009). An Introduction to Old Frisian. Amsterdam: John Benjamins B.V. ISBN 978-90-272-3255-7.
- Euler, Wolfram (2013). Das Westgermanische - von der Herausbildung im 3. bis zur Aufgliederung im 7. Jahrhundert - Analyse und Rekonstruktion (West Germanic: from its Emergence in the 3rd up until its Dissolution in the 7th Century CE: Analyses and Reconstruction). 244 p., in German with English summary, London/Berlin 2013, ISBN 978-3-9812110-7-8.
- (German) Maurer, Friedrich (1942) Nordgermanen und Alemannen: Studien zur germanischen und frühdeutschen Sprachgeschichte, Stammes- und Volkskunde, Strasbourg: Hüneburg.
- Ringe, Donald R. and Taylor, Ann (2014). The Development of Old English - A Linguistic History of English, vol. II, 632p. ISBN 978-0199207848. Oxford.
- (German) Sonderegger, Stefan (1979). Grundzüge deutscher Sprachgeschichte. Diachronie des Sprachsystems. Band I: Einführung – Genealogie – Konstanten. Berlin/New York: Walter de Gruyter. ISBN 3-11-003570-7.
- Volyes, Joseph B. (1992). Early Germanic Grammar: Pre-, Proto-, and Post-Germanic. San Diego: Academic Press. ISBN 0-12-728270-X.