同言線

同言線 （isogloss、heterogloss），也稱作等語線 ，是指某一個特定的語言學特徵的分佈地理界線 ，譬如，某個元音的發音、某個詞彙的意義、或是某種句法。方言界線的劃分一般就是許多條大致重疊的同言線 。

法罗群岛同言線.

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.

參考文獻

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

外部連結

• .
• : A discussion of the shortcomings and oversimplifications of using isoglosses.
• On Some Acoustic Correlates of Isoglossy （页面存档备份，存于互联网档案馆）: A humorous analysis of Russian isoglossy.