Modoc Indians
The Modoc Indian territory extended into the northern part of California. With the Klamath, the Modoc constituted the Lutuamian division of the Shapwailutan linguistic stock of the Penutian language family.

Penutian is a proposed grouping of language families that includes many Native American languages of western North America, predominantly spoken at one time in Washington, Oregon, and California.
The existence of a Penutian stock or phylum has been the subject of debate among specialists.
Even the unity of some of its component families have been disputed. Some of the problems in the comparative study of languages within the phylum are the result of their early extinction and minimal documentation.
Consensus was reached at a 1994 workshop on Comparative Penutian at the University of Oregon that the families within the proposed phylum’s California, Oregon, Plateau, and Chinookan clusters would eventually be shown to be genetically-related.
Subsequently, Tarpent reassessed Tsimshianic, a geographically isolated family in northern British Columbia, and concluded that its affiliation within Penutian is also probable.
Irrespective of the overall debate regarding Penutian, some of its more recently proposed subgroupings have been convincingly demonstrated.
The Miwokan and the Costanoan languages have been grouped into an Utian language family by Catherine Callaghan. Callaghan has more recently provided evidence supporting a grouping of Utian and Yokutsan into a Yok-Utian family.
There also seems to be convincing evidence for the Plateau Penutian grouping (originally named Shahapwailutan by J. N. B. Hewitt and John Wesley Powell in 1894) which would consist of Klamath-Modoc, Molala, and the Sahaptian languages (Nez Percé and Sahaptin).
The original Penutian hypothesis, offered in 1913 by Roland B. Dixon and Alfred L. Kroeber, focused upon the close relationships among five California language families listed below.
That original proposal has since been called alternately Core Penutian, California Penutian, or the Penutian Kernel.
In 1919 the same two authors published their linguistic evidence for the proposal.
The grouping, like many of Dixon & Kroeber’s other phylum proposals, was based mostly on shared typological characteristics and not the standard methods used to determine genetic relationships. Starting from this early date, the Penutian hypothesis was controversial.
Prior to Dixon and Kroeber’s 1913 Penutian proposal, Albert S. Gatschet had grouped Miwokan and Costanoan into a Mutsun group in 1877. (That grouping, now termed Utian, was later conclusively demonstrated by Catherine Callaghan.)
Then, in 1903 Dixon & Kroeber noted a “positive relationship” among Costanoan, Maidu, Wintun, and Yokuts within a “Central or Maidu Type, from which they excluded Miwokan (their Moquelumnan).
In 1910, Kroeber finally recognized the close relationship between the Miwokan and Costanoan languages.
In 1916 Edward Sapir expanded Dixon and Kroeber’s California Penutian family with a sister stock, Oregon Penutian, which included the Coosan languages and also the isolates Siuslaw and Takelma:
Oregon Penutian
Coosan languages
Siuslaw
Takelma
Later Sapir and Leo Frachtenberg added the Kalapuyan and the Chinookan languages and then later the Alsean and Tsimshianic families, culminating in Sapir’s 1921 four-branch classification:
I. California Penutian grouping
Maiduan (Maidu)
Utian (Miwok-Costanoan)
Wintuan (Wintu)
Yokutsan (Yokuts)
II. Oregon Penutian grouping
Coosan (Coos)
Siuslaw
Takelma
Kalapuyan (Kalapuya)
Alsean (Yakonan)
III. Chinookan family (Chinook)
IV. Tsimshianic family (Tsimshian)
By the time Sapir’s 1929 Encyclopædia Britannica article was published, he had added two more branches:
Plateau Penutian family
Klamath
-Modoc (Lutuami)
Waiilatpuan
Cayuse
Molala
Sahaptian
(Sahaptin)
Mexican Penutian grouping
Mixe-Zoque
Huave
resulting in a six-branch family:
California Penutian
Oregon Penutian
Chinookan
Tsimshianic
Plateau Penutian
Mexican Penutian
(Sapir’s full 1929 classification scheme including the Penutian proposal can be seen in his 1929 Encyclopedia Britannica article. )The 16th edition of Ethnoloque Languages of the World breaks the Penutian language classification into 33 languages:
Penutian (33)
California Penutian (1)
Wintuan (1)
Wintu [wit] (United States)
Chinookan (2)
Chinook [chh] (United States)
Wasco-Wishram [wac] (United States)
Maiduan (4)
Maidu, Northeast [nmu] (United States)
Maidu, Northwest [mjd] (United States)
Maidu, Valley [vmv] (United States)
Nisenan [nsz] (United States)
Oregon Penutian (5)
Coast Oregon (3)
Coosan (1)
Coos [csz] (United States)
Siuslawan (1)
Siuslaw [sis] (United States)
Yakonan (1)
Alsea [aes] (United States)
Kalapuyan (1)
Kalapuya [kyl] (United States)
Takelma (1)
Takelma [tkm] (United States)
Plateau Penutian (6)
Klamath-Modoc (1)
Klamath-Modoc [kla] (United States)
Sahaptin (5)
Nez Perce [nez] (United States)
Tenino [tqn] (United States)
Umatilla [uma] (United States)
Walla Walla [waa] (United States)
Yakima [yak] (United States)
Tsimshian (3)
Gitxsan [git] (Canada)
Nisga’a [ncg] (Canada)
Tsimshian [tsi] (Canada)
Unclassified (1)
Molale [mbe] (United States)
Yok-Utian (11)
Utian (10)
Costanoan (3)
Karkin [krb] (United States)
Ohlone, Northern [cst] (United States)
Ohlone, Southern [css] (United States)
Miwokan (7)
Eastern (5)
Western (2)
Yokuts (1)
Yokuts [yok] (United States)
The Modoc Indian territory extended into the northern part of California. With the Klamath, the Modoc constituted the Lutuamian division of the Shapwailutan linguistic stock of the Penutian language family.
The Yokuts Indians were originally considered a distinct linguistic family but have now been made a part of the large Penutian stock.
The Patwin formed the southernmost and most diverse dialetic division of the former Wintun (or Copehan) linguistic family, now considered part of the Penutian stock.
Originally a distinct stock in the classificatory system of Powell, Miwok has now been made a subdivision of the Penutian linguistic family.
The Wintu Indians were the northernmost division of the Copehan stock of Powell, later called Wintun by Kroeber (1932) and now regarded as part of the Penutian family.
Formerly considered an independent stock, the Maidu have now been placed in the Penutian linguistic family.