Initial identification of a distinct language occurred through study of one of the
Buddhist āgamas, the
Dīrghāgama, which had been translated into
Chinese by Buddhayaśas () and Zhu Fonian (). Since this time, a consensus has grown in scholarship which sees the first wave of Buddhist missionary work as associated with Gandhārī and the Kharoṣṭhī script, and tentatively with the Dharmaguptaka sect. Available evidence also indicates that the first Buddhist missions to Khotan were carried out by the Dharmaguptaka sect, and used a Kharoṣṭhī-written Gandhārī. However, there is evidence that other sects and traditions of Buddhism also used Gandhārī, and evidence that the Dharmaguptaka sect also used Sanskrit at times. Starting in the first century of the common era, there was a large trend toward a type of Gandhārī which was heavily Sanskritised. Linguistic evidence links some groups of the
Dardic languages with Gandhari. The
Kohistani languages, now all being displaced from their original homelands, were once more widespread in the region and most likely descend from the ancient dialects of the region of Gandhara. The last to disappear was
Tirahi, still spoken some years ago in a few villages in the vicinity of
Jalalabad in eastern Afghanistan, by descendants of migrants expelled from
Tirah by the
Afridi Pashtuns in the 19th century.
Georg Morgenstierne claimed that Tirahi is "probably the remnant of a dialect group extending from Tirah through the
Peshawar district into
Swat and
Dir." Nowadays, it must be entirely extinct and the region is now dominated by
Iranian languages brought in by later immigrations, such as
Pashto. ==Phonology==