Proto-Siouan language

Proto-Siouan, sometimes known as Proto-Siouan–Catawban, is the reconstructed ancestor of the Siouan languages. Although the attested daughter languages are largely native to the Great Plains region of the United States and Canada, Proto-Siouan is believed to have been originally spoken in and around the Ohio River Valley between 3000 BC and 2000 BC before splitting off into the Eastern and Western Siouan languages. Siouan-speaking peoples were eventually displaced or assimilated after losing several wars of conquest against their northern Iroquois neighbors during the 17th century, though their presence along the American Eastern Seaboard is supported by toponymic and onomastic data.

Proto-Siouan phonology had five oral and three nasal vowels, each distinguishable by length, and a complex set of consonants including a four-way stop distinction. The language also distinguished between at least two tones, high and non-high, though a falling tone may have also been present. Grammatically, the language was head-marking with simple agglutination. It has been reconstructed with an active–stative morphosyntactic alignment and subject–object–verb word order. The language also had a fairly complex morphophonology, using sound symbolism, phonesthemes, and apophony as ways of conveying semantic meaning, sometimes in combination.

As early as the first half of the 19th century, linguists have attempted to develop a broader understanding of the Siouan languages' relationships to other indigenous languages of the Americas. Early successes linked the larger Western Siouan family to the Catawban family, composed of two poorly attested languages, Catawba and Woccon, and there has been some acceptance of linking the family with the Yuchi language indigenous to eastern Tennessee. Wider attempts to link the language family variously to the Iroquoian, Caddoan, and Muskogean languages as well as a number of other language isolates have largely met with criticism and are not widely accepted.