isophonen.

1921 E. C. Roedder in Jrnl. Eng. & Germanic Philol. 20 182 The boundary lines of present dialects, with their maze of isophones,..and isotaxes, i.e., lines connecting places of identical or nearly identical sounds,..and syntactical peculiarities.

1926 Germanic Rev. I. iv. 303 Like the larger dialects, they would have to be portioned off against each other by isophones, isomorphs, isolexes, and isotaxes, i.e., lines of agreement in sound, form, word (meaning), and syntax.

1932 W. L. Graff Lang. & Langs. 364 There were isoglosses and isophones which contained the germs of later developments.

1935 Univ. Michigan Publ. Lang. & Lit. 13 32 The physiographical boundaries are an interpretation of the isophones and are therefore subject to the modifications that additional documentary evidence may bring. In some cases these modifications will result in a closer approximation of the isophones to the corresponding physiographical boundaries.

1936 Trans. Philol. Soc. 79 It certainly raises the question as to how far the delimitation of dialects and dialect features in Middle English by means of ‘isophones’ can really be reliable.

1937 Year's Work Eng. Stud. 1935 42 The country marked out by ‘isophonic’ lines into ten areas, each of which presents a more or less distinct complex of dialect-characteristics.

1955 W. S. Avis in Amer. Speech 30 7 In a very loose way this boundary approximates an r- isophone.

1970 Eng. Stud. 51 445 The new and very clear ā/ǭ isophone there [i.e. in Lincolnshire] is an important result of the investigation.

1926 Germanic Rev. 1 iv. 286 A map of France with all isophonic lines would show the wildest maze and confusion.

1935 Univ. Michigan Publ. Lang. & Lit. 13 23 We believe..that these isophonic lines do reflect roughly at least approximate boundaries for eleven of the most important characteristics of the regional dialects of Middle English as they existed about the middle of the fourteenth century.