Anisogloss, also called aheterogloss, is the geographic boundary of a certainlinguistic feature, such as thepronunciation of avowel, the meaning of a word, or the use of some morphological or syntactic feature. Isoglosses are a subject of study indialectology, in which they demarcate the differences between regionaldialects of a language; inareal linguistics, in which they represent the extent ofborrowing of features betweenlanguages in contact with one another; and in thewave model ofhistorical linguistics, in which they indicate the similarities and differences between members of alanguage family.
Majordialects are typically demarcated bybundles of isoglosses, such as theBenrath line that distinguishesHigh German from the otherWest Germanic languages and theLa Spezia–Rimini Line that divides the Northern Italian languages and Romance languages west of Italy from Central Italian dialects and Romance languages east of Italy. However, anindividual isogloss may or may not have any coterminus with alanguage border. For example, thefront-rounding of/y/ cuts across France and Germany, while the /y/ is absent from Italian and Spanish words that arecognates with the /y/-containing French words.
The termisogloss (Ancient Greekἴσοςísos 'equal, similar' andγλῶσσαglōssa 'tongue, dialect, language') is inspired bycontour lines, or isopleths, such asisobars. However, the isogloss separates rather than connects points. Consequently, it has been proposed for the termheterogloss (ἕτεροςhéteros 'other') to be used instead.[1]
In some branches (for exampleGreek,Italic andGermanic), the palatals merged with the velars: PIE*keup- "tremble (inwardly)" becameLatincupiō "desire" and*ḱm̥tom "hundred" became Latincentum (pronounced [kentum]); but*kʷo- "interrogative pronoun" becamequō "how? where?". They are known ascentum branches, named after the Latin word forhundred.
In other branches (for example,Balto-Slavic andIndo-Iranian), the labiovelars merged with the velars: PIE*keup- becameVedic Sanskritkopáyati "shaken" and*kʷo- becameAvestankō "who?"; but*ḱm̥tom became Avestansatəm. They are known assatem branches, after the Avestan word forhundred.[2][3]
Since the Balto-Slavic family, the Indo-Iranian family, and the othersatem families are spoken in adjacent geographic regions, they can be grouped by an isogloss: a geographic line separatingsatem branches on one side fromcentum branches on the other.
A feature of the ancientNorthwest Semitic languages isw becomingy at the beginning of a word. Thus, inProto-Semitic and subsequent non-NorthwestSemitic languages and dialects, theroot letters for a word for "child" werew-l-d. However, in the ancient Northwest Semitic languages, the word wasy-l-d, withw- >y-.
Similarly, Proto-Semiticā becomesō in theCanaanite dialects of Northwest Semitic.[4] Within theAramaic languages and dialects of Northwest Semitic, the historicā is preserved. Thus, an ancient Northwest Semitic language whose historicā becameō 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.[5]
For example, a distinguishing feature of theIron Age OldHebrew script is that the lettersbet,dalet,ayin andresh do not have an open head, but contemporaryAramaic has open-headed forms. Similarly, thebet of Old Hebrew has a distinctive stance (it leans to the right), but thebet of the Aramaic andPhoenician scripts series has a different stance (in both, it leans to the left).
In 2006,Christopher Rollston suggested using the termisograph 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.[6]
^Sihler, Andrew L. (2000).Language History. Current Issues in Linguistic Theory. Vol. 191. Amsterdam/Philadelphia: John Benjamins Publishing. p. 170.ISBN90-272-3698-4.
^Fortson IV, Benjamin W. (2004).Indo-European Language and Culture. Blackwell Publishing. pp. 52–54.ISBN1-4051-0316-7.
^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.doi:10.1086/BASOR25066977.S2CID160670117.
