Dialectology () is the scientific study of dialects and other forms of language variation, especially variation associated with geographic region. Dialectologists investigate differences in pronunciation, grammar, and vocabulary, and how such differences pattern across communities and change over time.
The field developed in the 19th century alongside historical linguistics and became closely associated with large-scale dialect surveys and the production of dialect maps and linguistic atlases. Such work typically relies on systematic data collection (for example, questionnaires, interviews, and recordings) and represents the geographic distribution of linguistic features using concepts such as isoglosses and dialect boundaries.
From the mid-20th century onward, dialectology has increasingly overlapped with sociolinguistics and variationist approaches, extending its focus from primarily rural, long-established speakers to include urban varieties, social differentiation, and the effects of migration and language contact. Topics commonly discussed in dialectological research include mutual intelligibility and the language–dialect distinction, diglossia, dialect continua, and the relationship between regional varieties and standard forms in pluricentric languages.
History
Early developments Dialectology emerged from nineteenth-century comparative work on the Indo-European languages, where variation across dialects and written records was used to infer earlier stages such as Proto-Indo-European. Developments in phonetics and sound change laws encouraged greater attention to living dialects as a source of linguistic data, since they preserve details often absent from written texts. Over time, this work helped establish dialects as objects of study in their own right.
English dialects In London, there were comments on the different dialects recorded in 12th-century sources, and a large number of dialect glossaries (focussing on vocabulary) were published in the 19th century.Petyt (1980), p.37 Philologists would also study dialects, as they preserved earlier forms of words.
In Britain, the philologist Alexander John Ellis described the pronunciation of English dialects in an early phonetic system in volume 5 of his series On Early English Pronunciation. The English Dialect Society was later set up by Joseph Wright to record dialect words in the British Isles. This culminated in the production of the six-volume English Dialect Dictionary in 1905. The English Dialect Society was then disbanded, as its work was considered complete, although some regional branches (e.g. the Yorkshire Dialect Society) still operate today.
Traditional studies in dialectology were generally aimed at producing dialect maps, in which lines were drawn on a map to indicate boundaries between different dialect areas. These maps displayed the geographical distribution of linguistic features using isoglosses, which are lines marking the boundaries where different linguistic variants are used. The move away from traditional methods of language study, however, caused linguists to become more concerned with social factors. Dialectologists, therefore, began to study social, as well as regional variation. The Linguistic Atlas of the United States (the 1930s) was amongst the first dialect studies to take social factors into account.
Under the leadership of Harold Orton, the University of Leeds became a centre for the study of English dialect and set up an Institute of Dialect and Folk Life Studies. In the 1950s, the university undertook the Survey of English Dialects, which covered all of England, some bordering areas of Wales, and the Isle of Man. In addition, the university produced more than 100 monographs on dialect before the death of Harold Orton in 1975. The institute closed in September 1983 to accommodate budget cuts at the university, but its dialectological studies are now part of a special collection, the Leeds Archive of Vernacular Culture, in the university's Brotherton Library.
This shift from purely regional to broader social factors in interest consequently saw the birth of sociolinguistics, which is a mixture of dialectology and social sciences. However, Graham Shorrocks has argued that there was always a sociological element to dialectology and that many of the conclusions of sociolinguists (e.g. the relationships with gender, class and age) can be found in earlier work by traditional dialectologists.
In the US, Hans Kurath began the Linguistic Atlas of the United States project in the 1930s, intended to consist of a series of in-depth dialectological studies of regions of the country. The first of these, the Linguistic Atlas of New England, was published in 1939. Kurath specified that at least two informants should be chosen from each county, representing different educational levels and ages, moving beyond earlier approaches that focused exclusively on elderly rural speakers. This methodological innovation introduced social stratification as an important dimension of linguistic geography. Later works in the same project were published or planned for the Middle Atlantic and South Atlantic states, for the North Central States, for the Upper Midwest, for the Rocky Mountain States, for the Pacific Coast and for the Gulf States,Petyt (1980), pp.43-44 though in a lesser degree of detail owing to the huge amount of work that would be necessary to fully process the data.
Later large-scale and influential studies of American dialectology have included the Dictionary of American Regional English, based on data collected in the 1960s and published between 1985 and 2013, focusing on lexicon; and the Atlas of North American English, based on data collected in the 1990s and published in 2006, focusing on pronunciation.
The sociolinguistic turn The development of variationist sociolinguistics in the 1960s, pioneered by William Labov, fundamentally transformed dialectology. Labov's 1963 study of Martha's Vineyard and his 1966 dissertation on the social stratification of English in New York City introduced quantitative methods and demonstrated that linguistic variation is systematically correlated with social factors such as class, age, and ethnicity. His famous New York City department store study showed how pronunciation of the post-vocalic /r/ varied systematically with the social prestige of different retail establishments, establishing that linguistic variables could serve as indicators of social status.
African American Vernacular English
African American Vernacular English (AAVE) has been an important focus of dialectological research. In the late 1960s and early 1970s, William Labov's studies of the linguistic features of AAVE were influential in establishing that it should not be stigmatized as substandard, but rather respected as a variety of English with its own systematic grammatical rules.
AAVE exhibits distinctive features across multiple linguistic levels. It is typically non-rhotic, dropping the /r/ sound when not followed by a vowel. The dialect includes features such as copula omission (e.g., "Sharon gon come"), the habitual or invariant "be" marking regularly occurring actions (e.g., "Billy don't be telling lies"), and intensified negation through double negatives (e.g., "She don wan nothin").
Research has shown that AAVE spread from its original rural Southern base to become predominantly urban and nationwide following the Great Migration, with contemporary urban features now diffusing back into rural areas. The study of AAVE has contributed significantly to dialectology by demonstrating how social factors like racial segregation, community identity, and socioeconomic status shape language development.
French dialects Jules Gilliéron published a linguistic atlas of 25 French-speaking locations in Switzerland in 1880. In 1888, Gilliéron responded to a call from Gaston Paris for a survey of the dialects of France, likely to be superseded by Standard French in the near future, by proposing the Atlas Linguistique de la France. The principal fieldworker for the atlas, Edmond Edmont, surveyed 639 rural locations in French-speaking areas of France, Belgium, Switzerland and Italy. The questionnaire initially included 1400 items, later increased to over 1900. The atlas was published in 13 volumes between 1902 and 1910.Petyt (1980), pp.41-42 The success of Gilliéron and Edmont's methods resulted in the construction of many linguistic atlases in the United States and throughout the world, establishing a model that influenced dialectological research for decades.
German dialects The first comparative dialect study in Germany was Die Mundarten Bayerns (The Dialects of Bavaria) in 1821 by Johann Andreas Schmeller, which included a linguistic atlas.Petyt, p.38
In 1873, L. Liebich surveyed the German-speaking areas of Alsace by a postal questionnaire that covered phonology and grammar. He never published any of his findings.Petyt (1980), p.39
In 1876, Eduard Sievers published Grundzüge der Phonetik (Elements of Phonetics) and a group of scholars formed the Neogrammarian school. This work in linguistics covered dialectology in German-speaking countries. In the same year, Jost Winteler published a monograph on the dialect of Kerenzen in the Canton of Glarus in Switzerland, which became a model for monographs on particular dialects.Petyt (1980), pp.39-40
Also in 1876, Georg Wenker, a young school librarian from Düsseldorf based in Marburg, sent postal questionnaires out over Northern Germany. These questionnaires contained a list of sentences written in Standard German. These sentences were then transcribed into the local dialect, reflecting dialectal differences. He later expanded his work to cover the entire German Empire, including dialects in the east that have become extinct since the territory was lost to Germany. Wenker's work later became the Deutscher Sprachatlas at the University of Marburg. After Wenker's death in 1911, work continued under Ferdinand Wrede and later questionnaires covered Austria as well as Germany.Petyt (1980), pp.40-41
Italian dialects and Corsican The first treatment of Italian dialects was by Dante Alighieri in his treatise De vulgari eloquentia in the early fourteenth century.
The founder of scientific dialectology in Italy was Graziadio Isaia Ascoli, who, in 1873, founded the journal Archivio glottologico italiano, still active today together with L'Italia dialettale, which was founded by Clemente Merlo in 1924, and the more recent Rivista italiana di dialettologia.
After completing his work in France, Edmond Edmont surveyed 44 locations in Corsica for the Atlas Linguistique de la Corse.Petyt (1980), p.41
Two students from the French atlas, Karl Jaberg and Jakob Jud, surveyed dialects in Italy and southern Switzerland in the Sprach- und Sachatlas Italiens und der Südschweiz.Petyt (1980), p.42 This survey influenced the work of Hans Kurath in the US.Petyt (1980), p.44
Scots dialects and Gaelic The Linguistic Survey of Scotland began in 1949 at the University of Edinburgh.Petyt (1980), p.94 The first part of the survey researched dialects of Scots in the Scottish Lowlands, the Shetland Islands, the Orkney Islands, Northern Ireland, and the two northernmost counties of England: Cumberland (since merged into Cumbria) and Northumberland. Three volumes of results were published between 1975 and 1985.Petyt (1980), pp.95-96 The second part studied dialects of Gaelic, including mixed use of Gaelic and English, in the Scottish Highlands and Western Isles. Results were published under the name of Cathair Ó Dochartaigh in five volumes between 1994 and 1997.
Concepts and terminology
Isoglosses