The English language in Northern England has been shaped by the region's history of settlement and migration, and today encompasses a group of related dialects known as Northern England English (or, simply, Northern English in the United Kingdom). The strongest influence on the modern varieties of the English language spoken in Northern England is the Northumbrian dialect of Middle English, but also contact with Old Norse during the Viking Age, with Irish English following the Great Famine and particularly in Lancashire and the south of Yorkshire, with Midlands dialects since the Industrial Revolution, have produced new and distinctive styles of speech. Some "Northern" traits can be found further south than others: only conservative Northumbrian dialects retain the pre-Great Vowel Shift pronunciation of words such as town (, ), but all northern accents lack the FOOT–STRUT split, and this trait extends a significant distance into the Midlands. There are traditional dialects associated with many of the historic counties, including the Cumbrian dialect, Lancashire dialect, Northumbrian dialect and Yorkshire dialect, but new, distinctive dialects have arisen in cities following urbanisation in the nineteenth and twentieth centuries: The Manchester urban area has the Manchester dialect (which is sometimes considered a part of the Lancashire dialect but sometimes separated), Liverpool and its surrounds have Scouse, Tyneside has Geordie and Yorkshire has Tyke. Many Northern English accents are stigmatised, and speakers often attempt to repress Northern speech characteristics in professional environments, although in recent years Northern English speakers have been in demand for call centres, where Northern stereotypes of honesty and straightforwardness are seen as a plus. Northern English is one of the major groupings of the English language in England; other major groupings include East Anglian English, East and West Midlands English, West Country (Somerset, Dorset, Devon, Cornwall) and Southern English English. Definition The varieties of English spoken across Great Britain form a dialect continuum, and there is no universally agreed definition of which varieties are Northern. The most restrictive definition of the linguistic North includes only those dialects spoken north of the River Tees. Other linguists, such as John C. Wells, describe these as the dialects of the "Far North" and treat them as a subset of all Northern English dialects. Conversely, Wells uses a very broad definition of the linguistic North, comprising all dialects that have not undergone the TRAP–BATH and FOOT–STRUT splits. Using this definition, the isogloss between North and South