[3] The exact number of Arapaho speakers is not precisely known; however it has been estimated that the language currently retains between 250 [4] and 1,000[1] active users.

[5] As of 2008, the authors of a newly published grammar estimated that there were slightly over 250 fluent speakers, plus "quite a few near-fluent passive understanders".

[6] Arapaho language camps were held in Summer 2015 at Wind River Tribal College and in St. Stephens, Wyoming.

[1] Besawunena, only attested from a wordlist collected by Kroeber, differs only slightly from Arapaho, though a few of its sound changes resemble those seen in Gros Ventre.

Arapaho is unusual among Algonquian languages in retaining the contrast between the reconstructed phonemes *r and *θ (generally as /n/ and /θ/, respectively).

[14] Arapaho has a series of four short vowels /i e o u/ (pronounced [ɪ ɛ ɔ ʊ]) and four long vowels /iː eː oː uː/ (customarily written ⟨ii ee oo uu⟩ and pronounced [iː ɛː ɔː uː]).

The difference in length is phonemically distinctive: compare hísiʼ, 'tick' with híísiʼ, 'day', and hócoo, 'steak' with hóócoo, 'devil'.

/u/ does have some exceptions as in the free variants kokíy ~ kokúy, 'gun'; kookiyón ~ kookuyón, 'for no reason'; and bííʼoxíyoo ~ bííʼoxúyoo, 'Found in the Grass' (a mythological character).

The phoneme /b/ (the voiced bilabial stop) has a voiceless allophone [p] that occurs before other consonants or at the end of a word.

At the "surface" (at the level of actual pronunciation), other clusters arise by phonological processes including vowel syncope, or by juxtaposition of morphemes.

[citation needed] Vowel-initial, onset-less syllables, however, can occur due to partitioning of vowel clusters.

Although tonal contrasts are distinctive in Arapaho, minimal pairs such as those listed above are rare.

[20] Arapaho is highly synthetic; verbs in particular take a large number of grammatical and semantic morphemes.

One pattern occurs for the class of nouns that have /ii/ or /uu/ (depending on vowel harmony) as their plural marker.

Notice in the examples below the usage of the transitive form requires the addition of INAN, the inanimate marker for the object (the shoes).

For example, the imperfective /ii/ morpheme becomes nii- instead of the expected hii- when prefixing verbs that would undergo initial change.

[33] As an example of animacy agreement, the intransitive verb for 'to fall' has a form that takes an inanimate subject, nihtéésceníse' (PAST-on top-fall(II)-0S)[34] and a form that takes an animate subject, nihtéés'cenísi.

This can be seen in the example below where 'walk' takes an argument that is composed of a composite proximate and obviative noun.

'Like all Algonquian languages, Arapaho has a rich arrary of preverbs expressing various meanings, in particular manner or aspect.

[36] hibernal cecin- 'during winter', vernal benii’ow- 'during the spring', estival biicen- 'during the summer' and autumnal toyoun-'during the fall' (Cowell and Moss 2006:217-218, Jacques 2023:545).

[44] There are multiple usages of reduplication in Arapaho including pluralizing implied, secondary, and inanimate objects of (di)transitive verbs; indicating repeating and habitual action (extend the space and time a verb occurs in general), and intensifying.

Some instances where noun phrases are preposed include introducing a new referent (or reintroducing one that was inactive) and creating contrast.

In the listing below, the first in the pair is treated as "higher" in the hierarchy and tends therefore to be the leftmost NP.

[O:[51]Scouts, 64]Verb-subject-(implied) object order[54] hé’ih’iixóoxookusééninoe’ih-ii-xooxookusee-ninoNPAST-IMPERF-REDUP.go through(AI)-4PLnúhu’nuhu’thishó3iio3-iiarrow-PLnííne’éénoniine’ee-nohere is-PL.OBV?híí3einóón.ii3einoon-[in]buffalo-OBV.PLhé’ih’iixóoxookuséénino núhu’ hó3ii nííne’ééno híí3einóón.e’ih-ii-xooxookusee-nino nuhu’ o3-ii niine’ee-no ii3einoon-[in]{NPAST-IMPERF-REDUP.go through(AI)-4PL} this arrow-PL {here is-PL.OBV?}

[55] Preposed NP[56] (here, the noun phrase meaning 'where the attack was taking place' precedes the verb 'see' to create emphasis) héetbisíítooni’eetoh-bisiitooni-’where-attack.PART.IMPERS-0Snóonoohóotóú’unoonoohoot-o’usee.REDUP(TI)-3PLtéí’yoonóh’o’te’iyoonehe’-o’child-PLhíseino’.isein-o’woman-PLhéetbisíítooni’ nóonoohóotóú’u téí’yoonóh’o’ híseino’.eetoh-bisiitooni-’ noonoohoot-o’u te’iyoonehe’-o’ isein-o’where-attack.PART.IMPERS-0S see.REDUP(TI)-3PL child-PL woman-PL'Women and children watched where the attack was taking place.'

[O:[51]Scouts, 70]Both NPs preceding Verb (uncommon)[57] (additional context: occurs under "contrastive focus") hoo3óó’o’oo3oo’o’sometéce’iitece’-iinight-PLnih’éí’inóú’u.nih-e’in-o’uPAST-know(TI)-3PLhoo3óó’o’ téce’ii nih’éí’inóú’u.oo3oo’o’ tece’-ii nih-e’in-o’usome night-PL PAST-know(TI)-3PL'Some knew the nighttime' [O:[51]Eagles, 93]Generally, noun modifiers occur before the noun.

For example, in the example below, note that the presentative 'here is' occurs before the demonstrative 'this'[58] ’oh’ohbuthowóóowooalsoniiyóúnoniiyou-nohere is-PLnihíínihiiwellnúhu’nuhu’thisnihíínihiiwellyóókoxuu.yookox-iiwillow-PL’oh howóó niiyóúno nihíí núhu’ nihíí yóókoxuu.’oh owoo niiyou-no nihii nuhu’ nihii yookox-iibut also {here is-PL} well this well willow-PL'And then there are these, well .

Unlike other particles in Arapaho, however, they are not a closed class and are instead derived from or composed of other morphemes.

[63] "nih’iicebéso’onóóno’nih-ii-cebeso’on-oono’PAST-IMPERF-chase(TA)-12/3sósoní’iisosoni’-iiShoshone-PLnéeyóuneeyouthere it ishoh’éni’ohe’en-i’mountain-LOCniihííhi’"niih-iihi’along-ADVnih’íí3i’.nih-ii-3i’PAST-say(AI)-3PL"nih’iicebéso’onóóno’ sósoní’ii néeyóu hoh’éni’ niihííhi’" nih’íí3i’.nih-ii-cebeso’on-oono’ sosoni’-ii neeyou ohe’en-i’ niih-iihi’ nih-ii-3i’PAST-IMPERF-chase(TA)-12/3 Shoshone-PL {there it is} mountain-LOC along-ADV PAST-say(AI)-3PL'“We were chasing the Shoshones along the mountain there,” they said.'

[O:[51]Shade Trees, 15] Article 1 of the Universal Declaration of Human Rights in Arapaho:Beisiihi' hineeniteeno' tohcebii'oo3i' beehni'iine'etii3i', beehnii3inou'u nuhu' neneehiisou'u niihenehiitoono noh bobooteenetiit.