“Altaic” is a common term applied by linguists to a number of language families, spread across Central Asia and the Far East and sharing a large, most likely non-coincidental, number of structural and morphemic similarities. At the onset of Altaic studies, these similarities were ascribed to the one-time existence of an ancestral language—“Proto-Altaic,” from which all these families are descended; circumstantial evidence and glottochronological calculations tentatively date this language to some time around the 6th–7th millennium bc, and suggest Southern Siberia or adjacent territories (hence the name “Altaic”) as the original homeland of its speakers. However, since the mid-20th century the dominant view in historical linguistics has shifted to that of an “Altaic Sprachbund” (diffusion area), implying that the families in question have not sprung from a common source, but rather have acquired their similarities over a long period of mutual linguistic contact. The bulk of “Altaic” has traditionally included such uncontroversial families as Turkic, Mongolic, and Manchu-Tungusic; additionally, Japanese (Japonic) and Korean are also frequently seen as potential members of the larger Altaic family (the entire five branches are sometimes referred to as “Macro-Altaic”). The debate over the nature of the relationship between the various units that constitute “Altaic,” sometimes referred to as “the Altaic controversy,” has been one of the most hotly debated topics in 20th-century historical linguistics and a major focal point of studies dealing with the prehistory of Central and East Eurasia. Supporters of “Proto-Altaic,” commonly known as “(pro-)Altaicists,” claim that only divergence from an original common ancestor can account for the observed regular phonetic correspondences and other structural similarities, whereas “anti-Altaicists,” without denying the existence of such similarities, insist that they do not belong to the “core” layers of the respective languages and are therefore better explained as results of lexical borrowing and other forms of areal linguistic contact. As a rule, “pro-Altaicists” claim that “Proto-Altaic” is as reconstructible by means of the classic comparative method as any uncontroversial linguistic family; in support of this view, they have produced several attempts to assemble large bodies of etymological evidence for the hypothesis, backed by systems of regular phonetic correspondences between compared languages. All of these, however, have been heavily criticized by “anti-Altaicists” for lack of methodological rigor, implausibility of proposed phonetic and/or semantic changes, and confusion of recent borrowings with items allegedly inherited from a common ancestor. Despite the validity of many of these objections, it remains unclear whether they are sufficient to completely discredit the hypothesis of a genetic connection between the various branches of “Altaic,” which continues to be actively supported by a small, but stable scholarly minority.
The Altaic languages (Turkic, Mongolic, Tungusic) are spread across Eurasia, from Central Asia to the Middle East and the Balkans. The genetic affinity between these subgroups has not been definitively established but the commonality among features and patterns points to some linguistic connections. The main morphological operations in Altaic languages are suffixation and compounding. Generally regarded as morphologically regular with easily identifiable suffixes in which there are clear form-meaning correspondences, the languages, nevertheless, show irregularities in many domains of the phonological exponents of morphosyntactic features, such as base modification, cumulative exponence, and syncretism. Nouns are inflected for number, person, and case. Case markers can express structural relations between noun phrases and other constituents, or they can act as adpositions. Only very few of the Altaic languages have adjectival inflection. Verbs are inflected for voice, negation, tense, aspect, modality, and, in most of the languages subject agreement, varying between one and five person-number paradigms. Subject agreement is expressed through first, second, and third persons singular and plural. In the expression of tense, aspect, and modality, Altaic languages employ predominantly suffixing and compound verb formations, which involve auxiliary verbs. Inflected finite verbs can stand on their own and form propositions, and as a result, information structure can be expressed within a polymorphic word through prosodic means. Affix order is mostly fixed and mismatches occur between morpholotactic constraints and syntactico-semantic requirements. Ellipsis can occur between coordinated words. Derivational morphology is productive and occurs between and within the major word classes of nominals and verbs. Semantic categories can block other semantic categories.