Tagdal (Tuareg name: Tagdalt)^[3] is a mixed Northern Songhay language of central Niger. Ethnologue considers it a "mixed Berber–Songhay language",^[1][4] while other researchers consider it Northern Songhay.^[5] There are two dialects: Tagdal proper, spoken by the Igdalen people, pastoralists who inhabit a region to the east along the Niger border to Tahoua in Niger,^[4] and Tabarog, spoken by the Iberogan people of the Azawagh valley on the Niger–Mali border.

Nicolaï (1981) uses the name Tihishit as a cover term. Rueck & Christiansen^[6] say that

...the Igdalen and the Iberogan have for many purposes been treated as one group, and their speech forms are closely related. Nicolaï uses "tihishit" as a common designator for these two speech forms...; however, this term is ambiguous. "Tihishit" is a term of Tamajaq origin meaning "the language of the blacks". The Igdalen and Iberogan used it to refer to all Northern Songhay speech forms.^[5]

Meanwhile, the Iberogan sometimes refer to their language as Tagdal.

Tagdal is an agglutinative language, most likely due to Tuareg influence.^[4]: 71