In particular, they are spoken in the cities of Timbuktu, Djenné, Niamey, Gao, Tillaberi, Dosso, Parakou, Kandi, Natitingou, Djougou, Malanville, Gorom-Gorom, In-Gall and Tabelbala .

[6] For linguists, a major point of interest in the Songhay languages has been the difficulty of determining their genetic affiliation; they are commonly taken to be Nilo-Saharan, as defined by Joseph Greenberg in 1963, but this classification remains controversial.

[7] Roger Blench argues that the Songhay and Saharan languages form a Songhay-Saharan branch with each other within the wider Nilo-Saharan linguistic phylum.

[12] Diedrich Hermann Westermann, a missionary and linguist, hesitated between assigning it to Gur or considering it an isolate, and Maurice Delafosse grouped it with Mande.

Roger Blench notes that Songhay shares the defining singulative–plurative morphology typical of Nilo-Saharan languages.

[13] Certain Songhay–Mande similarities have long been observed (at least since Westermann), and Mukarovsky (1966), Denis Creissels (1981) and Nicolaï (1977, 1984) investigated the possibility of a Mande relationship; Creissels made some 50 comparisons, including many body parts and morphological suffixes (such as the causative in -endi), while Nicolaï claimed some 450 similar words as well as some conspicuous typological traits.

[citation needed] However, Nicolaï eventually concluded that this approach was not adequate, and in 1990 proposed a distinctly novel hypothesis: that Songhay is a Berber-based creole language, restructured under Mande influence.

In support of this he proposed 412 similarities, ranging all the way from basic vocabulary (tasa "liver") to obvious borrowings (anzad "violin", alkaadi "qadi".)

Others, such as Gerrit Dimmendaal, were not convinced, and Nicolaï (2003) appears to consider the question of Songhay's origins still open, while arguing against Bender's proposed etymologies.

[citation needed] Greenberg's morphological similarities with Nilo-Saharan include the personal pronouns ai (cf.

Manding lá, Soso ra...)[citation needed] The Songhay languages are considered to be an independent family by Dimmendaal (2011), although he classifies Saharan as part of Nilo-Saharan.

[14] Songhay is mostly a tonal, SOV group of languages, an exception being the divergent Koyra Chiini of Timbuktu, which is non-tonal and uses SVO order.