Featural specification derives allomorphy in featural paradigms. Allomorphy in which different phonological exponents of the same feature bundle are idiosyncratically realized depending on the morphological or phonological environment is captured through contextual specification. An example of such allomorphy is the English plural marker. The typical English plural marker is /-z/, as in bulls. However, the plural of child is children, and the plural of cactus is cacti. Since the choice of the plural morpheme exponent is not related to features, but rather simply to the root it attaches to, the roots must be listed in the contextual specification: