This thesis is framed within the synchronic study of the Lancashire dialect (LanD) in the nineteenth century. Despite the previous studies on this dialect (Downing 1980; Hollman Willem & Siewerska 2007; Ruano-García 2007; Barras 2015), the phonological aspects of this vernacular variety still remain largely unexplored. Research on this dialect was mainly focused on the general linguistic phenomena of northern dialects or common dialect features of the LanD (Downing 1980; Barras 2015). As a result, the specific phonological traits of the LanD have not been thoroughly studied but within a broader category.This thesis aims at contributing to the knowledge of the phonological linguistic traits and the possible pronunciations of the Lancashire dialect during the 19th century. To illustrate the possible pronunciations of this dialect, I will examine the pronunciation of the Received Pronunciation (RP) diphthongs [aʊ], [aɪ], [ǝʊ], [ɛɪ], and [ɛǝ] and the RP monophthongs [i:], [ɜ:], [u:], [ɔ:], and [ɛ] in the dialect of Lancashire (Lan) in the XIX century. For this purpose, I will study the deviant spellings of these RP sounds in the XIX century literary-dialect works. This type of literature is a useful tool for dialect study as the representation of the deviant spellings provides evidence of the dialect pronunciations at a certain period of time...