Dialects are variations which occur within a language. We frequently give names to dialects which we consider to be different from that which is heard in the local area; for example, we talk of iaith Shir Gâr (Carmarthenshire language) and iaith Cwm Tawe (Swansea Valley language). However, we accept that all these varieties of spoken Welsh are valid representations of the same language, and that they are all part of Cymraeg or Welsh.

A crucial consideration when discussing dialect is the relationship of the language with the community which uses it. Language does not exist in a vacuum; it is devised and used by people. Dialects have developed over hundreds of years, and the influences on them have been many and varied.

Essentially, dialect can reflect the contact that has existed between its speakers and people from other areas, and their coming and going from place to place. When discussing Welsh dialect, much has been made of the supposed relationship between dialect boundaries and administrative boundaries in the Middle Ages. It would appear though that the root of the problem lies in the relationship between these boundaries and the geographical features which underlie them. It ought to be borne in mind that until comparatively recent times, natural barriers such as high mountains and wide rivers made it difficult for people from different areas to communicate effectively.

Modern improvements in transport and communications have made these geographical features less relevant, the population has become more mobile and the influences on this population have become more varied. Welsh-language education is quite widely available, and S4C beams the accents and styles of the whole country into our living-rooms on a daily basis. At the same time, the monoglot culture has disappeared, taking with it, to a large extent, the opportunity of hearing and learning the kind of language that was such a characteristic aspect of all our towns and villages.