The Brittoniclanguages form one of the two branches of the Insular Celtic language family; the other is Goidelic. It comprises the extant languages Breton, Cornish, and Welsh. The name Brythonic was derived by Welsh Celticist John Rhys from the Welsh word Brython, meaning Ancient Britons as opposed to an Anglo-Saxon or Gael.
The Celtic languages are a group of related languages descended from Proto-Celtic. They form a branch of the Indo-European language family. The term "Celtic" was first used to describe this language group by Edward Lhuyd in 1707, following Paul-Yves Pezron, who made the explicit link between the Celts described by classical writers and the Welsh and Breton languages.
The Goidelic or Gaelic languages form one of the two groups of Insular Celtic languages, the other being the Brittonic languages.
Pictish is an extinct Brittonic Celtic language spoken by the Picts, the people of eastern and northern Scotland from Late Antiquity to the Early Middle Ages. Virtually no direct attestations of Pictish remain, short of a limited number of geographical and personal names found on monuments and early medieval records in the area controlled by the kingdoms of the Picts. Such evidence, however, shows the language to be an Insular Celtic language related to the Brittonic language then spoken in most of the rest of Britain.
Insular Celtic languages are the group of Celtic languages spoken in Brittany, Great Britain, Ireland, and the Isle of Man. All surviving Celtic languages are in the Insular group, including Breton, which is spoken on continental Europe in Brittany, France. The Continental Celtic languages, although once widely spoken in mainland Europe and in Anatolia, are extinct.
Proto-Celtic, or Common Celtic, is the hypothetical ancestral proto-language of all known Celtic languages, and a descendant of Proto-Indo-European. It is not attested in writing but has been partly reconstructed through the comparative method. Proto-Celtic is generally thought to have been spoken between 1300 and 800 BC, after which it began to split into different languages. Proto-Celtic is often associated with the Urnfield culture and particularly with the Hallstatt culture. Celtic languages share common features with Italic languages that are not found in other branches of Indo-European, suggesting the possibility of an earlier Italo-Celtic linguistic unity.
In historical linguistics, Italo-Celtic is a hypothetical grouping of the Italic and Celtic branches of the Indo-European language family on the basis of features shared by these two branches and no others. There is controversy about the causes of these similarities. They are usually considered to be innovations, likely to have developed after the breakup of the Proto-Indo-European language. It is also possible that some of these are not innovations, but shared conservative features, i.e. original Indo-European language features which have disappeared in all other language groups. What is commonly accepted is that the shared features may usefully be thought of as Italo-Celtic forms, as they are certainly shared by the two families and are almost certainly not coincidental.
The Continental Celtic languages are the now-extinct group of the Celtic languages that were spoken on the continent of Europe and in central Anatolia, as distinguished from the Insular Celtic languages of the British Isles and Brittany. Continental Celtic is a geographic, rather than linguistic, grouping of the ancient Celtic languages.
The Britons, also known as Celtic Britons or Ancient Britons, were an indigenous Celtic people who inhabited Great Britain from at least the British Iron Age until the High Middle Ages, at which point they diverged into the Welsh, Cornish, and Bretons. They spoke Common Brittonic, the ancestor of the modern Brittonic languages.
The Celtic nations or Celtic countries are a cultural area and collection of geographical regions in Northwestern Europe where the Celtic languages and cultural traits have survived. The term nation is used in its original sense to mean a people who share a common identity and culture and are identified with a traditional territory.
The various names used since classical times for the people known today as the Celts are of disparate origins.
Celtic toponymy is the study of place names wholly or partially of Celtic origin. These names are found throughout continental Europe, Britain, Ireland, Anatolia and, latterly, through various other parts of the globe not originally occupied by Celts.
The Goidelic substrate hypothesis refers to the hypothesized language or languages spoken in Ireland before the arrival of the Goidelic languages.
The Insular Celts were speakers of the Insular Celtic languages in the British Isles and Brittany. The term is mostly used for the Celtic peoples of the isles up until the early Middle Ages, covering the British–Irish Iron Age, Roman Britain and Sub-Roman Britain. They included the Celtic Britons, the Picts, and the Gaels.
Brittonicisms in English are the linguistic effects in English attributed to the historical influence of Brittonic speakers as they switched language to English following the Anglo-Saxon settlement of Britain and the establishment of Anglo-Saxon political dominance in Britain.
Common Brittonic, also known as British, Common Brythonic, or Proto-Brittonic, is an extinct Celtic language spoken in Britain and Brittany.
Gaulish is an extinct Celtic language spoken in parts of Continental Europe before and during the period of the Roman Empire. In the narrow sense, Gaulish was the language of the Celts of Gaul. In a wider sense, it also comprises varieties of Celtic that were spoken across much of central Europe ("Noric"), parts of the Balkans, and Anatolia ("Galatian"), which are thought to have been closely related. The more divergent Lepontic of Northern Italy has also sometimes been subsumed under Gaulish.
Neo-Brittonic, also known as Neo-Brythonic, is a stage of the Insular Celtic Brittonic languages that emerged by the middle of the sixth century CE. Neo-Brittonic languages include Old, Middle and Modern Welsh, Cornish, and Breton, as well as Cumbric.