Klallam, Clallam, Ns'Klallam or S'klallam (endonym: nəxʷsƛ̕ay̕əmúcən, /nxʷst͡ɬʼajˀˈmut͡sn/), is a Straits Salishan language historically spoken by the Klallam people at Becher Bay on Vancouver Island in British Columbia and across the Strait of Juan de Fuca on the north coast of the Olympic Peninsula in Washington.

Klallam is closely related to the Northern Straits Salish dialects, Sooke, Lekwungen, Saanich, Lummi, and Samish[7] but the languages are not mutually intelligible.

"[9] Beginning fall 2020, the Klallam language has been taught at Peninsula College in Port Angeles.

The last native speaker of Klallam as a first language was Hazel Sampson of Port Angeles, who died on February 4, 2014, at the age of 103.

[10] Hazel Sampson had worked along with brother Ed Sampson (d. 1995), Tom Charles (d. 1999), Bea Charles (d. 2009) and Adeline Smith (d. 2013), other native speakers of Klallam, and with language teacher Jamie Valadez and linguist Timothy Montler from 1992 to compile the Klallam Dictionary.

[10] In 1999, this effort led to the development of a lesson plan and guidebooks to teach students the basics of the language through storytelling.

[8] Bilingual English-Klallam street signs were installed at two intersections in Port Angeles in 2016.

[11] In 2020, Donald Sullivan, a member of the Port Gamble S'Klallam Tribe, installed street signs in Klallam alongside existing English ones in Little Boston.

[16] However, there is much reason to doubt this theory, as ʔaʔ, ʔiʔ, and ʔuʔ are all contrasting words, and there are likely more minimal pairs between vowels that exist in the language.

In its component parts, /ʔəs-xʷ-naʔnáʔ-yaʔ-ŋ-əs/ means "be in a state of small laughing on the face" or more simply, "smiling".

Allomorphy is common; often, a single affix with have multiple phonetic realizations due to stress structure or the phonology of the word it is being added to.

These prefixes can be added to nouns, adjectives and verbs to project ideas of time into the root's meaning.

[8][13] Klallam has lexical suffixes, which are unique to the languages of northwest North America.

[8][13] To create a diminutive form the first consonant is reduplicated with an additional 'suffix' of -aʔ afterwards and an infix of -ʔ- later in the word, which may be replaced by glottalization.

There is additionally a middle voice in which the suffix -əŋ on an intransitive stem creates an antipassive construction indicating an agent subject.