An isogloss, also called a heterogloss (see Etymology below), is the geographic boundary of a certain linguistic feature, such as the pronunciation of a vowel, the meaning of a word, or the use of some morphological or syntactic feature. Major dialects are typically demarcated by bundles of isoglosses, such as the Benrath line that distinguishes High German from the other West Germanic languages and the La Spezia–Rimini Line that divides the Northern Italian dialects from Central Italian dialects. However, an individual isogloss may or may not have any coincidence with a language border. For example, the front-rounding of /y/ cuts across France and Germany, while the /y/ is absent from Italian and Spanish words that are cognates with the /y/-containing French words.

One of the best-known isoglosses is the centum-satem isogloss.

Similar to an isogloss, an isograph is a distinguishing feature of a writing system. Both concepts are also used in historical linguistics.

Faroe islands isoglosses
Isoglosses on the Faroe Islands
German dialectal map
High German subdivides into Upper German (green) and Central German (blue), and is distinguished from Low Franconian and Low German (yellow). The main isoglosses, the Benrath and Speyer lines, are marked in black.


Centum-satem isogloss

The centum-satem isogloss of the Indo-European language family relates to the different evolution of the dorsal consonants of Proto-Indo-European (PIE). In the standard reconstruction, three series of dorsals are recognised:

Labiovelars: *kʷ, *gʷ, *gʷʰ
Velars: *k, *g, *gʰ
Palatals: *ḱ, , *ǵʰ

In some branches (for example Greek, Italic and Germanic), the palatals merged with the velars: PIE *keup- "tremble (inwardly)" became Latin cupiō "desire" and *m̥tom "hundred" became Latin centum (pronounced [kentum]); but *o- "interrogative pronoun" became quō "how? where?". They are known as centum branches, named after the Latin word for hundred.

In other branches (for example, Balto-Slavic and Indo-Iranian), the labiovelars merged with the velars: PIE *keup- became Vedic Sanskrit kopáyati "shaken" and *o- became Avestan "who?"; but *ḱm̥tom became Avestan satəm. They are known as satem branches, after the Avestan word for hundred.[1][2]

Since the Balto-Slavic family, the Indo-Iranian family, and the other satem families are spoken in adjacent geographic regions, they can be grouped by an isogloss: a geographic line separating satem branches on one side from centum branches on the other.

North-Midland isogloss (American English)

A major isogloss in American English has been identified as the North-Midland isogloss, which demarcates numerous linguistic features, including the Northern Cities vowel shift: regions north of the line (including Western New York; Cleveland, Ohio; lower Michigan; northern Illinois; and eastern Wisconsin) have the shift, while regions south of the line (including Pennsylvania, central and southern Ohio, and most of Indiana) do not.

Northwest Semitic

A feature of the ancient Northwest Semitic languages is w becoming y at the beginning of a word. Thus, in Proto-Semitic and subsequent non-Northwest Semitic languages and dialects, the root letters for a word for "child" were w-l-d. However, in the ancient Northwest Semitic languages, the word was y-l-d, with w- > y-.

Similarly, Proto-Semitic ā becomes ō in the Canaanite dialects of Northwest Semitic.[3] Within the Aramaic languages and dialects of Northwest Semitic, the historic ā is preserved. Thus, an ancient Northwest Semitic language whose historic ā became ō can be classed as part of the Canaanite branch of Northwest Semitic.

Such features can be used as data of fundamental importance for the purposes of linguistic classification.


Just as there are distinguishing features of related languages, there are also distinguishing features of related scripts. (For a discussion of writing systems, see The World's Writing Systems.[4])

For example, a distinguishing feature of the Iron Age Old Hebrew script is that the letters bet, dalet, 'ayin and resh do not have an open head, but contemporary Aramaic has open-headed forms. Similarly, the bet of Old Hebrew has a distinctive stance (it leans to the right), but the bet of the Aramaic and Phoenician scripts series has a different stance (in both, it leans to the left).

In 2006, Christopher Rollston suggested using the term isograph to designate a feature of the script that distinguishes it from a related script series, such as a feature that distinguishes the script of Old Hebrew from Old Aramaic and Phoenician.[5]


The term isogloss (Ancient Greek ἴσος ísos "equal, similar" and γλῶσσα glōssa "tongue, dialect, language") is inspired by contour lines, or isopleths, such as isobars. However, the isogloss separates rather than connects points. Consequently, it has been proposed for the term heterogloss (ἕτερος héteros "other") to be used instead.[6]

See also


  1. ^ Fortson IV, Benjamin W. (2004). Indo-European Language and Culture. Blackwell Publishing. pp. 52–54. ISBN 1-4051-0316-7.
  2. ^ Rix, Helmut (2001). Lexikon der indogermanischen Verben. Dr. Ludwig Reichert Verlag. p. 359. ISBN 3-89500-219-4.
  3. ^ Garr, W. Randall (2 June 2008). Dialect Geography of Syria-Palestine: 1000-586 BCE. Eisenbrauns. ISBN 1-57506-091-4.
  4. ^ Daniels, Peter; Bright, William, eds. (8 February 1996). The World's Writing Systems. New York: Oxford University Press. ISBN 0-19-507993-0.
  5. ^ Rollston, Christopher A. (2006). "Scribal Education in Ancient Israel: The Old Hebrew Epigraphic Evidence". Bulletin of the American Schools of Oriental Research. 344: 47–74.
  6. ^ Sihler, Andrew L. (2000). Language History. Current issues in linguistic theory. 191. Amsterdam/Philadelphia: John Benjamins Publishing. p. 170. ISBN 90-272-3698-4.


  • Chambers, J.K.; Trudgill, Peter (28 December 1998). Dialectology. Cambridge Textbooks in Linguistics (2nd ed.). Cambridge University Press. ISBN 0-521-59646-7.
  • Woodard, Roger D. (31 May 2004). The Cambridge Encyclopedia of the World's Ancient Languages. New York: Cambridge University Press. ISBN 0-521-56256-2.

External links


Benrath may refer to:

Düsseldorf-Benrath, a part of the city of Düsseldorf in Germany

Schloss Benrath, a historical building in Düsseldorf-Benrath

Benrath line, a term of German linguistics (the maken-machen isogloss)

Benrath line

In German linguistics, the Benrath line (German: Benrather Linie) is the maken–machen isogloss: dialects north of the line have the original /k/ in maken (to make), while those to the south have the innovative /x/ (machen). The Line runs from Benrath (part of Düsseldorf) and Aachen to eastern Germany near Frankfurt an der Oder in the area of Berlin and Dessau and later in Prussian dividing Low Prussian dialect and High Prussian dialect.

The High German consonant shift (3rd to 9th centuries AD), in which the (northern) Low German dialects for the most part did not participate, affected the southern varieties of the West Germanic dialect continuum. This shift is traditionally seen to distinguish the High German varieties from the other West Germanic languages.

The impact of the High German consonant shift increases gradually to the South. The Benrath line does not mark the northernmost effect of the High German consonant shift, since the Uerdingen line, the ik–ich isogloss, lies slightly further north; and some of the peripheral changes associated with the shift did affect Low German.

Central German

Central German (German: mitteldeutsche Dialekte, mitteldeutsche Mundarten, Mitteldeutsch) is a group of High German dialects spoken from the Rhineland in the west to the former eastern territories of Germany.

Central German divides into two subgroups, West Central German and East Central German.

Central German is distinguished by having experienced only the first and fourth phases of the High German consonant shift. It is spoken in the linguistic transition region separated from Northern Germany (Low German/Low Franconian) by the Benrath line isogloss. It is separated from Southern Germany (Upper German) by the Speyer line.

Central German is spoken in large and influential German cities like the capital Berlin, the former West German capital Bonn, Cologne, Düsseldorf and the main German financial center Frankfurt.

The area corresponds to the geological region of the hilly Central Uplands that stretches from the North German plain to the South German Scarplands, covering the states of Saarland, Rhineland-Palatinate, Hesse, Thuringia and Saxony.

Centum and satem languages

Languages of the Indo-European family are classified as either centum languages or satem languages according to how the dorsal consonants (sounds of "K" and "G" type) of the reconstructed Proto-Indo-European language (PIE) developed. An example of the different developments is provided by the words for "hundred" found in the early attested Indo-European languages. In centum languages, they typically began with a /k/ sound (Latin centum was pronounced with initial /k/), but in satem languages, they often began with /s/ (the example satem comes from the Avestan language of Zoroastrian scripture).

The table below shows the traditional reconstruction of the PIE dorsal consonants, with three series, but according to some more recent theories there may actually have been only two series or three series with different pronunciations from those traditionally ascribed. In centum languages, the palatovelars, which included the initial consonant of the "hundred" root, merged with the plain velars. In satem languages, they remained distinct, and the labiovelars merged with the plain velars.

The centum–satem division forms an isogloss in synchronic descriptions of Indo-European languages. It is no longer thought that the Proto-Indo-European language split first into centum and satem branches from which all the centum and all the satem languages, respectively, would have derived. Such a division is made particularly unlikely by the discovery that while the satem group lies generally to the east and the centum group to the west, the most eastward of the known IE language branches, Tocharian, is centum.

Gallo language

Gallo is a regional language of France. It is not as commonly spoken as it once was, as the standard form of French now predominates. Gallo is classified as one of the Oïl languages.

Gallo was originally spoken in the Marches of Neustria, which now corresponds to the border lands of Brittany and Normandy and its former heart in Le Mans, Maine. Gallo was the shared spoken language of several of those who took part in the Norman conquest of England, most of whom originated in Lower Brittany and Lower Normandy. Thus, Gallo was a vehicle for the subsequent transformation ("Gallicisation") of English, along with the Norman language.

Gallo continued as the language of Higher Brittany, Maine and some neighbouring portions of Normandy until the introduction of universal education across France, but today Gallo is spoken by only a small minority of the population, having been largely superseded by standard French.

As an Oïl language, Gallo forms part of a dialect continuum which includes Norman, Picard and the Poitevin dialect, among others. One of the features that distinguish it from Norman is the absence of Old Norse influence. There is some limited mutual intelligibility with adjacent varieties of the Norman language along the linguistic frontier and with Guernésiais and Jèrriais. However, as the dialect continuum shades towards Mayennais, there is a less clear isogloss. The clearest isogloss is that distinguishing Gallo from Breton, a Brittonic Celtic language traditionally spoken in the western territory of Brittany.

In the west, the vocabulary of Gallo has been influenced by contact with Breton, but remains overwhelmingly Latinate. The influence of Breton decreases eastwards across Gallo-speaking territory.

As of 1980, Gallo's western extent stretches from Plouha (Plóha), in Côtes-d'Armor, south of Paimpol (Paimpol), passing through Châtelaudren (Châtié), Corlay (Corlaè), Loudéac (Loudia), east of Pontivy (Pontivy), Locminé (Lominoec), Vannes (Vannes) and ending in the south, east of the Rhuys peninsula, in Morbihan.

Hard and soft G in Dutch

Hard and soft G in Dutch (Dutch: harde en zachte G) refers to a phonological phenomenon of the pronunciation of the letters ⟨g⟩ and ⟨ch⟩ and also a major isogloss within that language.

In northern dialects of Dutch, the letters represent velar ([ɣ] and [x], respectively) or uvular fricatives [χ], the so-called hard G.

However, in most northern dialects, the distinction is no longer made, with both sounds pronounced as [x] or [χ]. In those dialects that merge ⟨g⟩ and ⟨ch⟩, it is still possible for some speakers to pronounce ⟨g⟩ as [ɣ] intervocallically.

In many southern dialects of Dutch, ⟨g⟩ and ⟨ch⟩ represent front-velar fricatives ([ɣ̟] and [x̟]), the so-called soft G.

High Prussian dialect

High Prussian (German: Hochpreußisch) is the group of East Central German dialects in former East Prussia, in present-day Warmian-Masurian Voivodeship, Poland. High Prussian developed in the 13th–15th centuries, brought in by German settlers mainly from Silesia and Thuringia, and was influenced by the Baltic Old Prussian language.

High Prussian dialects were spoken mainly in the Catholic region of Warmia and adjacent East Prussian Oberland region beyond the Passarge River in the west (around Preußisch Holland and Mohrungen), subdivided into Breslausch (from Silesian Breslau) and Oberländisch. They were separated from the Low Prussian dialect area by the Benrath line isogloss to the west, north and east; to the south they bordered on the Polish Masurian dialect region.

Like Silesian German, High Prussian is moribund due to the evacuation and expulsion of the German-speaking population from the Province of East Prussia during and after World War II. The dialect has few remaining speakers today.

Joret line

The Joret line (French: ligne Joret) is an isogloss used in the linguistics of the langues d'oïl. Dialects North and West of the line have preserved Vulgar Latin /k/ and /ɡ/ before /a/; dialects South and East of the line have palatalized /k/ and /ɡ/ before /a/. This palatalization gave Old French /tʃ/ and /dʒ/, then modern French /ʃ/ and /ʒ/. The line was first identified by Charles Joret and published in 1883.

To the North and West of the line lie the Picard language and some dialects of the Norman language. To the South and the East lie other Oïl dialects including southern Norman, Walloon and French. The area North and West of the ligne Joret is sometimes called the Normano-Picard domain.


Krefeld (German pronunciation: [ˈkʁeːfɛlt] (listen)), also known as Crefeld until 1929, is a city in North Rhine-Westphalia, Germany. It is located northwest of Düsseldorf, its centre lying just a few kilometres to the west of the river Rhine; the borough of Uerdingen is situated directly on the Rhine. Krefeld is accessed by the autobahns A57 (Cologne–Nijmegen) and the A44 (Aachen–Düsseldorf–Dortmund–Kassel).

Krefeld is also called the "Velvet and Silk City".

Krefeld's residents speak Hochdeutsch, or standard German, but the native dialect is a Low German variety, sometimes locally called Krefelder Plattdeutsch, Krieewelsch Platt, Plattdeutsch, or sometimes simply Platt. The Uerdingen line isogloss, separating general dialectical areas in Germany and neighboring Germanic-speaking countries, runs through and is named after Krefeld's Uerdingen district, originally an independent municipality.

Laan van Meerdervoort

The Laan van Meerdervoort (Dutch pronunciation: [ˈlaːn vɑn ˈmeːrdərvoːrt]) is an avenue in The Hague. At a length of 5.8 km, it is (as of 2011) the longest avenue in the Netherlands.The Laan van Meerdervoort is more or less an isogloss of two subvarieties of The Hague dialect. The posher variety called dàftig, Haegs or bekakt Haags is spoken roughly north of it, whereas a low-class variety called plat Haags or Hèègs is spoken roughly south of the Laan van Meerdervort.

Nord (French department)

Nord (French pronunciation: ​[nɔʁ]; English: North; Dutch: Noorderdepartement) is a department in the far north of France. It was created from the western halves of the historical counties of Flanders and Hainaut, and the Bishopric of Cambrai. The modern coat of arms was inherited from the County of Flanders.

Nord is the country's most populous department. It also contains the metropolitan region of Lille, the fifth-largest urban area in France after Paris, Lyon, Marseille, and Toulouse. Within the department is located the part of France where the French Flemish dialect of Dutch is still spoken (along with French) as a native language. Like Dutch, the dialect of Ch'ti [[1]] is still spoken.

Pochutec language

Pochutec is an extinct Uto-Aztecan language of the Nahuan (or Aztecan) branch which was spoken in and around the town of Pochutla on the Pacific coast of Oaxaca, Mexico. In 1917 it was documented in a monograph by Franz Boas, who considered the language nearly extinct. In the 1970s another investigator found two speakers around Pochutla who still remembered a few of the words recorded by Boas.In the early 20th century, scholars disagreed as to the origin of the language within the Nahuan family. Most thought Pochutec was distinct from Nahuatl, and this was proven in 1978, when Campbell and Langacker gave new arguments from Boas' data. Their conclusion was quickly accepted. Nahuan thus consists of Pochutec and General Aztec, which consists of Nahuatl and Pipil.

Bartholomew (1980) suggests that some of the divergent traits, for example last syllable stress, are due to influence from Chatino, an Oto-Manguean language. She argues that at the time of the 16th century Spanish conquest of Mexico the settlement of Pochutla did not fall under the Aztec Empire's domain, but instead was part of the Mixtec state centered at Tututepec. Thus, the Chatino linguistic influences stemmed from the trade and communication routes between Pochutla and Tututepec passing through Chatino territory.

Dakin (1983) argues that the key correspondence sets used by Campbell and Langacker as evidence for the existence of a separate fifth vowel *ï evolving from pUA *u, their main basis for separating Pochutec from their "General Aztec", were actually later developments within Pochutec by which proto-Aztec *i and *e > o in closed syllables, and that the supposed contrast in final position in imperatives originally had had a following clitic. In a later article, Canger and Dakin (1985) identify a different, very systematic isogloss for the development of pUA *u that shows a basic split between Eastern Nahuatl dialects and the Central and Western periphery, including Pochutec, as exemplified in at least eight different cognate sets. This proposal is incompatible with Campbell and Langacker's proposal for the development of pUA *u. Dakin thus classifies Pochutec as belonging to the Western branch of the Nahuan languages, rather than having split off from Nahuan before the basic East-West split.


Småländska (Swedish for "Smålandian") is the accent of Swedish spoken in the historical province of Småland in southern Sweden. The northeastern accents are mainly influenced by the Central Swedish accents while the southwest has been more influenced by Southern Swedish accents, like that of Halland and Scania. Among the most distinguishing features of southern Småländska is the use of a uvular trill [ʀ] (most often realized as a voiced uvular fricative [ʁ]) for the Swedish phoneme /r/.

A major isogloss runs straight through Småland in a rough line from the border to Västergötland in the west through Jönköping and to the coastal town of Mönsterås in the east, 40 km north of Kalmar. The isogloss divides the dorsal realizations of /r/ in the south and the transitional area that uses both coronal and dorsal realization encompassing large parts of Västergötland, Östergötland, Värmland and Bohuslän. North of this transitional area only coronal realizations such as alveolar trills [r], alveolar taps [ɾ] and voiced retroflex fricatives [ʐ] are used.

Speyer line

In German linguistics, the Speyer line, or Main line (Main river) is an isogloss separating the dialects to the north, which have a geminated (lengthened) stop in words like Appel "apple", from the dialects to the south, which have an affricate: Apfel. The line begins in Alsace near Strasbourg, and runs north-east to Thüringen, crossing the Rhine at Speyer. After passing close to Erfurt, it turns south-east and continues into the formerly German-speaking parts of Bohemia. It can be observed well by the fact that place-names containing an uncombined /p/ phoneme mostly lie to the north of the line (Paderborn, Potsdam, Wuppertal), while those with an affricate /pf/ (Pfaffenhofen, Pforzheim) mostly lie to the south.

Uerdingen line

The Uerdingen Line (named after Uerdingen by Georg Wenker) is the isogloss within West Germanic languages that separates dialects which preserve the -k sound in the first person singular pronoun word "ik" (north of the line) from dialects in which the word final -k has changed to word final -ch in the word "ich" (IPA [ç]) (south of the line). This sound shift is the one that progressed the farthest north among the consonant shifts that characterize High German and Middle German dialects. The line passes through Belgium, the Netherlands, and Germany.

North of the line Low German and Dutch are spoken. South of the line Central German is spoken. In the area between the Uerdingen line and the Benrath line to its south, which includes parts of Belgium and the Netherlands, the Germanic dialect Limburgish is spoken. Especially in eastern Germany, the regional languages have been largely replaced by standard German since the 20th century.

The western end of the Uerdingen line is at Bierbeek, southwest of Leuven, Flemish Brabant, Belgium. From there, it runs in northeastern direction, north of Hasselt and Weert, Netherlands, from where it goes straight east. It passes south of Venlo to cross into Germany's Rhineland. It passes through Kempen and Krefeld-Hüls, and crosses the Rhine between Krefeld-Uerdingen and Duisburg-Mündelheim. From there, the isogloss passes south of Mülheim an der Ruhr-Saarn, and Essen-Kettwig, where it turns southeast. It continues past Wuppertal-Elberfeld, Gummersbach and Bergneustadt. Further east, it forms the border of the Sauerland (to its north) and the Siegerland (to its south). It passes north of Kassel, south of Magdeburg and north of Wittenberg. In southern Brandenburg in eastern Germany, the isogloss runs by Halbe, Hermsdorf, Freidorf and Staakow.

Watford Gap

Watford Gap is a low-lying area between two hills, close to the village of Watford, Northamptonshire, England. Engineers from Roman times onwards have found it to be an ideal route for connecting the Midlands with South East England. The A5 road, the West Coast Main Line railway, the M1 motorway and a branch of the Grand Union Canal traverse in parallel a space about 400 metres (1,300 ft) wide. It has been written and spoken of as marking the divide between Northern England and Southern England.

West Central German

West Central German (German: Westmitteldeutsche Dialekte) belongs to the Central, High German dialect family in the German language. Its dialects are thoroughly Franconian and comprise the parts of the Rhinelandic continuum located south of the Benrath line isogloss, including the following sub-families:

Central Franconian (Mittelfränkisch)

Ripuarian (Ripuarisch), spoken in North Rhine-Westphalia (including Kölsch) and German-speaking Belgium and a small edge in the south of the Dutch province of Limbourg.

Moselle Franconian (Moselfränkisch) in Rhineland-Palatinate, Saarland and France (francique mosellan)

Luxembourgish (Lëtzebuergesch, luxembourgeois) in Luxembourg, Belgium and France (francique luxembourgeois)

Riograndenser Hunsrückisch, spoken in Brazil and derived from the Hunsrückisch dialect of Moselle Franconian

Rhine Franconian (Rheinfränkisch, francique rhénan)

Palatinate Franconian (Pfälzisch, francique palatin), spoken in Rhineland-Palatinate

Lorraine Franconian (Lothringisch, francique lorrain) in the French region of Lorraine

Bukovina German (Bukowinadeutsch) in Bukovina (extinct)

Pennsylvania German (Pennsylvaniadeutsch) in historical communities in North America, especially in Pennsylvania.

Hessian (Hessisch) in Hesse and the Rhenish Hesse region of Rhineland-Palatinate

North Hessian (Nordhessisch)

Central Hessian (Mittelhessisch)

East Hessian (Osthessisch)Apart from West Central German on the southern edge and in south-east Franconian dialects are turning to Upper German. This transition area between Central German and Upper German is captured by the dialect families of South Franconian German and East Franconian German, colloquially miscalled Franconian as dialects of this sub-family are spoken all over Franconia.

West Central German was spoken in several settlements throughout America, for example in the Amana Colonies.

Yugambeh–Bundjalung languages

Yugambeh–Bundjalung, also known as Bandjalangic is a branch of the Pama–Nyungan language family, that is spoken in northeastern New South Wales and South-East Queensland.

Yugambeh–Bundjalung was historically a dialect continuum consisting of a number of varieties, including Yugambeh, Nganduwal, Minjangbal, Njangbal, Biriin, Baryulgil, Waalubal, Dinggabal, Wiyabal, Gidabal, Galibal, and Wudjeebal; Language varieties in the group vary in degree of mutual intelligibility, with varieties at different ends of the continuum being mostly unintelligible. These dialects formed 4 clusters -

Tweed-Albert Language (Yugambeh)

Condamine-Upper Clarence (Githabul)

Lower Richmond (Eastern Bundjalung – Minyangbal and Bandjalang proper)

Middle Clarence (Western Bundjalung)Bowern (2011) lists Yugambeh, Githabul, Minyangbal, and Bandjalang as separate Bandjalangic languages. All Yugambeh–Bundjalung languages are nearly extinct. Bandjalang proper has the greatest number of speakers: 113, while the other dialects have a total of 26 speakers.Gowar (Guwar) and Pimpama may be related to the Bandjalangic languages rather than to Durubalic.

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