Pictish is a term used for the extinct language or languages thought to be spoken by the Picts, the people of northern and central Scotland in the Early Middle Ages. The idea that a distinct Pictish language was perceived at some point is only attested clearly in Bede's early 8th century Historia ecclesiastica gentis Anglorum, and there is not enough evidence to test either the language's sprachraum or its coherency as a dialect continuum.
What evidence there is of the language is limited to place names and to the names of people found on monuments and the contemporary records in the area controlled by the Kingdom of the Picts at its height. At its height, it may have been spoken from Shetland down to Fife. The term "Pictish" was used by Jackson, and followed by Forsyth, to mean the language spoken mainly north of the Forth-Clyde line in the Early Middle Ages. They use the term "Pritennic" to refer to the language spoken in the Iron Age in this area that was the precursor to Pictish. Some scholars believe that there was an earlier non-Celtic language. However, sometimes the term "Pictish" is used to refer to the earlier language.

Language Classification
Among the ogham stones in Scotland there is a small subset that do not have Gaelic inscriptions. These are generally assumed to be in Pictish as they date from the Early Middle Ages. However, many alternative languages have been suggested - from non-Indo-European to Norse. It may have been that an older language was retained for inscriptions, in a similar way to Latin.
According to W. B. Lockwood (1975) the view that Pictish was a Celtic language is tentative. Referring to an inscription in Shetland he writes: "When the personal names are extracted, the residue is entirely incomprehensible. Thus the Lunnasting stone in Shetland reads ettocuhetts ahehhttann hccvvevv nehhtons. The last word is clearly the commonly occurring name Nechton, but the rest, even allowing for the perhaps arbitrary doubling of consonants in Ogam, appears so exotic that philologists conclude that Pictish was a non-Indo-European language of unknown affinities". Jackson considered that the language of the inscriptions was a different one from that of the place-names. However, Forsyth has interpreted these inscriptions as a Celtic language. Henri Guiter in 1968 concluded that the language was a form of Basque, which might tie in with DNA studies of pre-historic migrations.

Inscriptions
However, the evidence of place names and personal names argue strongly that at some point at least some of the people in the Pictish area spoke Insular Celtic languages related to the more southerly Brythonic languages