Plural is never marked morphologically on the noun itself.
There is a (non-obligatory) definite plural determiner (see also Feature 28 "Definite articles"); indefinite plurals are not marked at all.
The reduplication of nouns to express multitude is rare; it may be typical of the European variety (Bakratongo). Relatively more frequent is reduplication expressing a distributive plural.
Source: Schumann 1783: 21
Source: SPT 1762: 180
Source: Schumann 1783: 67
Source: Weygandt 1798: 139