Isophones or isographs? A problem in historical dialectology

The Onomastic Data of the Fourteenth-Century Poll Tax Returns: A Case for Further Dialectological Study of Late Medieval English

“…In an attempt to address the fundamental problems faced in the preparation of a historical dialect atlas, Fisiak (1982: 121) asked, among other questions, "what span of time can be recognized as a sufficiently homogenous unit for a description of dialects so that a historical change is not accepted as a dialect feature?". Unfortunately, the preferred answer to this question has been incompatible with the amount of data available for previous research, as stated by Fisiak (1982), There is no principled solution to this problem. So far only practical considerations have determined whether it should be a hundred years or more.…”

“…He writes: "In my long preoccupation with Middle English dialects I have become more and more convinced that documents of the type Lay Subsidy Rolls and Court Rolls provide the most reliable material for a survey of Middle English dialects " (1997: 655). Fisiak (1982) provides further support for the use of such records in historical dialectology, stating that Subsidy roles [sic] and assize roles [sic] and in fact any lists of names in legal documents are extremely important and should not be neglected (cf. Sundby 1963).…”

"Mandeville’s Travels" and the study of Middle English word geography: a corpus-based analysis of selected verbs

“…The main difference concerning present-day and historical dialectology is that the data in the latter case can only be collected on the basis of the existing written sources (Fisiak 1982). First of all, many texts or manuscripts did not survive till present.…”

“…Despite of this, the tools used for historical dialectology make this discipline "an important laboratory for the achievement of increasingly reliable findings" (Dossena and Lass 2009: 7). Fisiak (1982) proposes to divide the functions of historical dialectology into static (synchronic) and dynamic. Static functions aim at "establishing isoglosses (consequently producing atlases) for certain periods in the history of a language" (ibid.…”