According to Merriam Webster Dictionary, accent is a way of speaking typical of a particular group of people and especially of the natives or residents of a region.

Accent according to Britannica is the property of a syllable which makes it stands out in an utterance relative to its neighbouring syllables. The emphasis on the accented syllable relative to the unaccented syllables may be realized through greater length, higher or lower pitch, a changing pitch contour, greater loudness or a combination of these characteristics.

Accent has various domains which are the word, the phrase and the sentence. Word accent which is also known as word stress or lexical stress is part of the characteristic way in which a language is pronounced. Given a particular language system, word accent may be fixed, predictable or movable as in English. 

Although some linguists include phonological features such as vowels, consonants and intonation among the dimensions of dialect, the standard practice is to treat such features as aspects of accent. In the sound system of American English for example, some speakers pronounce "greasy" with an /s/ sound, while others pronounce it with a /z/ sound. Accent differences of this kind are extremely important as regional and class indicators in every language. Their role is recognized in certain place such as Great Britain, where the prestige accent, called Received Pronunciation is used as an educated standard and differences in regional accents both rural and urban. 

According to Collins Dictionary, dialectology is the scientific study of dialects and dialectal variations. Dialectology looks at different accents and dialect communities and how these linguistic varieties can differ in several aspects including vocabulary, grammar and pronunciation. It also looks at other speakers’ attitudes towards this variation. Variation most commonly occurs as a result of relative geographic or social isolation.

Dialectology as a discipline began in the 19th century with the development in Western Europe of dictionaries and grammars of regional dialects. Dialectologists work hard to gather information about the types of variation that occur in different dialects and the construction of linguistic atlases showing patterns of distribution for a series of varying features within a language. Such work on the geographic patterns of linguistic variation is also known as linguistic geography. 

The most widespread type of dialectal differentiation is regional or geographic. As a rule, the speech of one locality differs at least slightly from that of any other place. Differences between neighbouring local dialects are usually small but differences is obvious in further region. Every dialectal feature has its own boundary line called an isogloss. Frequently, several isoglosses are grouped approximately together into a bundle of isoglosses. This grouping is caused by geographic obstacles that arrest the diffusion of a number of innovations along the same line or by historical circumstances such as political borders of long-standing or by migrations that have brought into contact two populations whose dialects were developed in noncontiguous areas.