Among the categories grammaticalised in the noun phrase, the domain of number shows several formal and functional similarities in genetically distinct languages of Amdo. In most languages of the area, it is grammaticalised in a complex way, with several morphemes expressing distinct plural categories. This paper describes the attested categories and their functional characteristics in order to retrace cases of linguistic copying and show the respective contribution of each language group to this domain. Hence, the paper shows that the grammatical domain of plurality in Amdo, both from a functional and a formal point of view, presents characteristics of linguistic convergence based on multiple model-languages.