North Sea Germanic

North Sea Germanic, also known as Ingvaeonic (/ˌɪŋviːˈɒnɪk/ ING-vee-ON-ik), is a subgrouping of West Germanic languages that consists of Old Frisian, Old English, and Old Saxon, and their descendants. These languages share a number of commonalities, such as a single plural ending for all persons of the verb, the Ingvaeonic nasal spirant law, common changes to the Germanic vowel *a, a plural form -as, and a number of other features which make scholars believe they form a distinct group within West Germanic.

It is debated whether the shared features of North Sea Germanic are inherited from a common proto-language or formed through later contact and influence. Additionally, the membership of the group is sometimes debated. Some scholars exclude Low German for lacking a number of features associated with North Sea Germanic. Other scholars include Dutch for sharing some features with the group.

The name Ingvaeonic derives from ancient Roman sources such as Tacitus, who describes a tribal group called the Ingvaeones. In current scholarship, the term "North Sea Germanic" is often preferred, as it is more descriptive of where these languages are spoken and also more neutral as to whether any connection exists to the Ingvaeones. Other names used include "Coastal Germanic" and "North Sea West Germanic."

The North Sea Germanic languages are usually defined as consisting of the Anglo-Frisian languages (English and Frisian) and Low German. Scholars debate whether these languages shared a single proto-language, or whether their common features are the result of contact and influence - some of them are also shared with the North Germanic languages. Some features may be common inherited features and others are likely areal features.

The status of Low German in the group is sometimes questioned, but most scholars believe that its oldest attested form, Old Saxon, shows clear North Sea Germanic features. Low German has been steadily influenced by High German, causing it to lose some of its North Sea Germanic features and become a linguistic "hybrid". Other scholars have argued that Old Saxon was always variable and represents a transitional dialect between North Sea Germanic and "Franconian". Much variation between North Sea Germanic and Franconian features in the language is dialectal; generally, eastern dialects show more Ingvaeonic phonetic features whereas western ones show more "Franconian" features.

Some scholars have argued that Dutch belongs to the North Sea Germanic languages, as it shares some characteristics with the others. On the other hand, there are arguments for grouping Old Saxon and Old Low Franconian (the ancestor of Dutch) together, as they also share features that are lacking in Anglo-Frisian. Within Dutch, forms that resemble those of the North Sea Germanic languages are called "Ingvaeonisms". These can be further divided into older Ingvaeonisms, which are found throughout Low Franconian, and younger Ingvaeonisms, which are only found in the coastal areas.

Throughout Northwest Germanic (North Germanic and West Germanic), stressed *u lowered to *o when *a was found in the next syllable:

However, *u was not lowered before a nasal consonant and a following consonant: