Drinfield describes it as containing three distinct, but related languages: Mukweym, Orok, and Aro.
There are two major dialects of Aro: anjəŋ səlep 'language of the Selep people', which is spoken in the villages of Selep, Brau, Mup, Fatundu, Wisamol, Afua, and Riworip, and anjəŋ mæləŋ 'language of the Meleng people', which is spoken in King and Kolembi.
While they are closely related and to an extent mutually intelligible, they are considered by native speakers to be distinct languages.
Drinfield hypothesizes that they form part of the Kombioic branch of the Kombio-Arapeshan subgroup, along with Eitiep, Aruek, and Kombio.
A weight of one is assigned to syllable with a short vowel nucleus and no consonant coda.
A weight of two is assigned to syllable with a short vowel nucleus and consonant coda.
Demonstratives in Aro have severals meanings: the temporal, locative, pronominal, and adnominal ones.
There are five prepositions: ka, similar to English 'of' and denoting possession, ki 'from', kap/kæp/kep 'similar to', nābət 'with', and paləu/pəlau 'about, for'.
[7] ɨjɨkwomannābətwitheyŋmanø-arkɨtNON1.PL-run.away.PLACTø-akwiNON1.PL-go.PLACTø-alpNON1.PL-go.towardkwæmvillageñābotNyambotɨjɨk nābət eyŋ ø-arkɨt ø-akwi ø-alp kwæm ñābotwoman with man NON1.PL-run.away.PLACT NON1.PL-go.PLACT NON1.PL-go.toward village NyambotThe woman and the man ran away to Nyambot village.In Aro, some nouns can be partially reduplicated in the first syllable to produce another noun.
While not a form of plurality marking, this reduplication generally results in an increase in magnitude for the noun, as in fon 'bush/forest', and fəfon 'various forests and gardens surrounding a village'.
Only four human nouns mark plurality, these being eyŋ ‘man/husband’, ɨjɨk ‘woman/wife’, bwaygɨp ‘male’, and lanɨŋ ‘child’.
The prefix a- derives a verb from a noun or adjective, as in ayiprau 'steal' (from yiprau 'thievery').
The irregular pluractional verb 'go' features the unrelated stems of first person tuki and non-first perso akwi.
Stems that undergo this change include ayurk > ɨyurk 'go in front', acoley > əcoley 'beat', and nawər > nuwər 'cross a bridge'.
The irrealis mood is triggered by negation, the future, the imperative, counterfactual statements, and when following paləu used in the sense of 'for/in order to'.
Superlatives are expressed through comparative construction lutreeədenthisləlapilong.PLisinagainpaləuPREPlaŋthatlu əden ləlapi isin paləu laŋtree this long.PL again PREP thatThese trees are taller than those onesNominal phrases are head-initial; that is, the head noun is followed by all adjectives, demonstratives, numerals, and some types of possessors.
However, optional third-person pronouns marking definiteness and some possessive constructions generally proceed the noun.
Phrases produced by speakers generally follow the noun + adjective + numeral + demonstrative sequence.
æ1SGm-akər1-seekārɨphouseñumwālnewwiyeutwoədenthisæ m-akər kārɨp ñumwāl wiyeu əden1SG 1-see house new two thisI saw these two new housesSimilar to languages like Yapunda, a 'classificatory' noun often precedes a more specific noun, like wuc 'wild animal' in wuc weləu 'tree kangaroo'.
Adjectival, nominal, possessive, demonstrative, numerical and prepositional clauses need not contain a copula.
kārɨphouseacəremptykārɨp acərhouse emptyThe houses were emptyNegation is placed between the subject and the predicate.
æ1SGm-əgān1-comem-əgāl1-take.NONPLACTeyŋmanm-ārəŋ1-sit.NONPLACTtəbauAfuaæ m-əgān m-əgāl eyŋ m-ārəŋ təbau1SG 1-come 1-take.NONPLACT man 1-sit.NONPLACT AfuaI came and got married in AfuaAdverbs are usually placed after the verb and its complements.
sa/save was borrowed from Tok Pisin The standard negation particle is aro, which triggers the irrealis mood in verbal predicates and is placed between the subject and the verb.