I. Background

Tēsu-Arar (pronounced [tēsy-aɹaɹ]) is a Tesian language of the Durimic / Northern Navari family, distributed throughout the Haraz Basin and across much of the central Deresmar plains. It functions as the principal administrative, liturgical, and literary medium within the Dur-Ti cultural sphere. The best described contemporary form is Duric Tēsu-Arar, a more conservative, codified standard derived from the Classical register preserved in temple archives and state inscriptions. Its sister language, Tēsu-Jar, is an old Tēsu form that has survived post-writing reform and contains many of the linguistic ambiguities that led to the standardisation of Tēsu-Arar. Additionally, it uses a syllabary-like form of the Tesian Glyphs to represent sounds. Unless otherwise specified, the present profile describes the Duric standard and its basin-wide dialect continuum, rather than attempting a full diachronic reconstruction of earlier stages.

The Durimic macrofamily descends from Proto-Durimic, which was introduced to Deresmar during late glacial migrations from the Yagida Archipelago between 14,000 and 12,000 BP. Reconstructions link these populations with early littoral and riverine settlements along the southern interior of Deresmar. Environmental disruption in the Yagida Archipelagos, including coastal inundation, volcanic activity, and prolonged subsistence stress, precipitated multiple migration waves toward the mainland. The largest and most persistent settlement complexes formed along the Haraz and Shushan river systems, where Proto-Durimic diversified into the Weranic, Tesian, and High Saravine branches. In early Dur-Ti societies, navigation, trade, and ritual leadership were institutionally feminised, with clan affiliation and inheritance traced primarily through maternal lines. Dur-Ti historiography associates these institutions with lexicalised gender distinctions and with durable norms of matrilineal organisation, both of which remain reflected in the morphosyntax of Tesian varieties. For the purposes of linguistic description, the primary relevance of early social organisation lies in its long-term correlation with grammaticalised gender, feminine-pronoun defaultism, and animacy categories in the nominal and agreement systems.

II. Classification

Within the Durimic family, three branches are recognised on the basis of shared innovations in phonology and morphosyntax. The Weranic languages of the western highlands, including Weren, Mensura, and Keshdar, preserve conservative vowel harmony and prosodic residue attributed to Proto-Durimic. Tesian languages of the Haraz Basin, represented by Tēsu-Arar, Darukha, Sideraj, Tēsu-Jar, Varina, Maradun, and Perisar, are characterised by a stable series of retroflex consonants. High Saravine languages of the northern plateau, such as Uhen, Tirna, Marén, Sárai, and Vélin, exhibit increased analytic structure, common vowel-length contrasts, and tonal or pitch-accent systems in certain varieties. Within Tesian languages, Tēsu-Arar and its closest relatives are historically associated with the Haraz and Suhsan river corridors. The Tēsu language functioned as an administrative and liturgical register within local polities and later within the Grand Darkhan Confederation. Tēsu-Arar is a prescriptive continuation of this register. The basin-wide continuum remains internally diverse but structurally coherent, with most variation attributable to redictable sound change, contact-induced lexical transfer, and local regularisation of agreement and case marking.

III. Geographic Distribution

Tēsu-Arar is spoken throughout the Haraz Basin, a broad endorheic depression in central Deresmar, bordered by highlands to the north and east. The basin was formerly occupied by Lake Haraz, which desiccated several millennia ago, leaving fertile alluvial plains sustained by the Haraz and Shushan river systems. Settlement density is highest on the river floodplains and on the former lakebed, where agricultural intensification and temple-centred administration facilitated the continuous transmission of language. The contemporary speech area extends from the upper Haraz corridor in the west to the Shushan headwaters in the east, encompassing both rural agrarian districts and a network of historic temple sites. Speaker populations are unevenly distributed, with a large proportion resident in the central basin urban centres and smaller populations distributed along the two river corridors and the surrounding foothill rim. Peripheral communities in the western uplands and northern plateaus frequently exhibit stable multiculturalism with Weranic and High Saravine varieties, and code-switching between the Jar and Arar varieties is common during pilgrimages.

Linguistic diversity within the basin is extensive, with more than thirty documented varieties of Tēsu traditionally grouped into four zones. Central Basin dialects (in the urban belt) dominate the former lakebed and exhibit the least divergence from the standard, with the lowest rates of morphophonological divergence from the ancient Tēsu-Arar varieties. Western (upper Haraz) dialects retain some of the more conservative retroflex articulations and older case allomorphs. Eastern (Shushan corridor & Tributary) dialects show more contact-conditioned phonological innovations than Eastern and Central dialects, especially compared with nearby Saravine-speaking populations with whom they have habitual contact. Highland & Basin Rim peripheral dialects show the strongest incidence of lenition and rounding processes, along with mild simplification of inflexion in informal registers.

Mutual intelligibility remains high among central basin varieties and is supported by the Duric standard used in administration, education, and temple liturgy. Comprehension declines toward the upland margins, where phonological neutralisations and contact-induced morphosyntactic simplification are most frequent.