In historical linguistics

Historical linguistics

Historical linguistics is the study of language change. It has five main concerns:* to describe and account for observed changes in particular languages...

, the Ingvaeonic

Ingvaeonic

Ingvaeonic , also known as North Sea Germanic, is a postulated grouping of the West Germanic languages that comprises Old Frisian, Old English and Old Saxon....

 nasal spirant law (also called the Anglo-Frisian

Anglo-Frisian languages

The Anglo-Frisian languages form a group of West Germanic languages consisting of Old English, Old Frisian, and their descendants...

or North Sea Germanic nasal spirant law) is a description of a phonological development in some dialects of West Germanic, which is attested in Old English

Old English language

Old English or Anglo-Saxon is an early form of the English language that was spoken and written by the Anglo-Saxons and their descendants in parts of what are now England and southeastern Scotland between at least the mid-5th century and the mid-12th century...

, Old Frisian, and Old Saxon. By this sound change, in the combination vowel

Vowel

In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...

 + nasal

Nasal consonant

A nasal consonant is a type of consonant produced with a lowered velum in the mouth, allowing air to escape freely through the nose. Examples of nasal consonants in English are and , in words such as nose and mouth.- Definition :...

 + fricative, the nasal disappeared, with compensatory lengthening

Compensatory lengthening

Compensatory lengthening in phonology and historical linguistics is the lengthening of a vowel sound that happens upon the loss of a following consonant, usually in the syllable coda...

 of the vowel. ("Spirant" is an older term for "fricative".) The sequences in question are original -ns-, -mf-, and -nþ-. The sequence -nh- underwent the same change, but already within late Proto-Germanic itself several hundred years earlier, so it is not unique to the Ingvaeonic languages alone.

Examples

Compare the first person plural pronoun "us" in various old Germanic languages:

Gothic Gothic language Gothic is an extinct Germanic language that was spoken by the Goths. It is known primarily from the Codex Argenteus, a 6th-century copy of a 4th-century Bible translation, and is the only East Germanic language with a sizable Text corpus...  uns Old High German Old High German The term Old High German refers to the earliest stage of the German language and it conventionally covers the period from around 500 to 1050. Coherent written texts do not appear until the second half of the 8th century, and some treat the period before 750 as 'prehistoric' and date the start of...  uns Middle Dutch Middle Dutch Middle Dutch is a collective name for a number of closely related West Germanic dialects which were spoken and written between 1150 and 1500...  ons

Old English Old English language Old English or Anglo-Saxon is an early form of the English language that was spoken and written by the Anglo-Saxons and their descendants in parts of what are now England and southeastern Scotland between at least the mid-5th century and the mid-12th century...  ūs Old Frisian Old Frisian Old Frisian is a West Germanic language spoken between the 8th and 16th centuries in the area between the Rhine and Weser on the European North Sea coast. The Frisian settlers on the coast of South Jutland also spoke Old Frisian but no medieval texts of this area are known...  ūs West Flemish West Flemish West Flemish , , , Fransch vlaemsch in French Flemish) is a group of dialects or regional language related to Dutch spoken in parts of the Netherlands, Belgium, and France....  uus Limburgian oos, ós Old Saxon Old Saxon Old Saxon, also known as Old Low German, is the earliest recorded form of Low German, documented from the 8th century until the 12th century, when it evolved into Middle Low German. It was spoken on the north-west coast of Germany and in the Netherlands by Saxon peoples...  ūs

Gothic represents East Germanic, and its correspondence to German and Standard Dutch shows it retains the more conservative form. The /n/ has disappeared in English, Frisian, Low German, and dialectal Dutch with compensatory lengthening

Compensatory lengthening

Compensatory lengthening in phonology and historical linguistics is the lengthening of a vowel sound that happens upon the loss of a following consonant, usually in the syllable coda...

 of the /u/.

Likewise:

• Germanic *tanþs → English tooth, North Frisian tôs, toss (vs. Low German Tähn, Dutch tand, German Zahn).
• Germanic *anþeraz → English other, West Frisian oar, West Flemish (Frans-Vlaams) aajer, Old Saxon ōðar, āthar (vs. Low German anner, German/Dutch ander [þ→d]).
• Germanic *gans → English goose, West Frisian goes, guos, Low German Goos (vs. Dutch gans, German Gans).
• Germanic *fimf → English five, West Frisian fiif, East Frisian fieuw, Dutch vijf, Low German fiev, fief (vs. German fünf).
• Germanic *samftō, -ijaz → English soft, West Frisian sêft, Low German sacht, Dutch zacht [ft→xt] (vs. German sanft).

English

English shows the results of the shift consistently throughout its repertoire of native lexemes. One consequence of this is that English has very few words ending in -nth; those that exist must have entered the vocabulary subsequent to the productive period of the nasal spirant law:

• month - derives from Old English monaþ (cf. German Monat); the intervening vowel rendered the law inapplicable here.
• tenth - from Middle English
  Middle English
  Middle English is the stage in the history of the English language during the High and Late Middle Ages, or roughly during the four centuries between the late 11th and the late 15th century....
  
   tenthe. The original Germanic *tehundô, which was regularised to *tehunþô in early Ingvaeonic, was affected by the law, producing Old English teogoþa, tēoþa (Modern English tithe). But the force of analogy with the cardinal number ten caused Middle English speakers to recreate the regular ordinal and re-insert the nasal consonant.
• plinth - a loanword in Modern English
  Modern English
  Modern English is the form of the English language spoken since the Great Vowel Shift in England, completed in roughly 1550.Despite some differences in vocabulary, texts from the early 17th century, such as the works of William Shakespeare and the King James Bible, are considered to be in Modern...
  
   from Greek
  Greek language
  Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
  
  ( "brick, tile").

Likewise, the rare occurrences of the combinations -nf-, -mf- and -ns- have similar explanations.

• answer - originally had an intervening dental: Old English andswaru.
• unfair - the prefix un- is still productive.

Dutch

Standard Dutch tends not to show a shift, but coastal dialects apply the spirant law to a greater extent, shifting some words but not others, e.g., standard Dutch mond 'mouth' vs. Holland mui (earlier muide) 'slit between sandbanks where tidal streams flow into'. This is due to the fact that standard Dutch, based mostly on the coastal dialect of South Holland, which in turn was influenced by Frisian, was nonetheless heavily influenced by the unshifted Brabantine dialect:

German

Modern Standard German is based on High German varieties, which are not affected by the shift, but contains some words from North German dialects that do reflect it. So for example, alongside sanft German also has sacht, both meaning "soft", "gentle".