Blocking [...] Morphemes in Nimboran display a remarkable ability to repel one another. As Anceaux repeatedly observes, the occurrence of certain morphemes in the verb is sufficient to "blockade", or prevent, the occurrence of certain other morphemes. A certain amount of morpheme incompatibility is, of course, attributable to semantic or syntactic feature clash. For example, the fact that the subject of a verb can never simultaneously be dual and plural has the unexciting consequence that the DuSubj "-k-" and the PlSubj <"i"> are in complementary distribution. [...] this type of blocking [...] we may characterize as intrinsic or "featural blocking" [...].
- Inkelas (2004), a pag.267