A large portion of its vocabulary however derives from a past variety of Swahili, today the lingua franca of much of East Africa's coast.
This Swahili influence is usually attributed to traders from Kilwa or elsewhere on the Zanzibar Coast, who in the fifteenth century settled at Angoche.
The main economic activity of men in the villages is fishing; the catch is sold on the markets of Angoche.
In Makhuwa, the dominant regional language of much of northern Mozambique, the Koti are called Maka, just like other coastal Muslim communities that were part of the Indian Ocean trading network.
In case of word-final 'i' it is sometimes accompanied with glide formation: olíli áka → olíly'aáka 'my bed'.
Words in Koti show incompatibility of aspirated consonants; this phenomenon is dubbed Katupha's Law in Schadeberg (1999), and is found in related Makhuwa languages as well.
Another incompatibility concerns dental and retroflex consonants, which never occur together within a stem, and usually assimilate when brought together.
Tone is not lexically distinctive for verbs, but it is very important in verbal inflection and in some other parts of grammar.
In kaláwa, High doubling is canceled because Final Lowering applies, so the last syllable has a Low tone.