One speaks of extrinsic ordering when the order of application of two rules must be specifically indicated and does not follow from a general principle. In Arabic the survival of a long vowel in a syllable made closed by a contraction may be a case of such ordering, though it may also be interpreted as an instrinsically ordered sequel of 'nonproductive -- operative' rules. On the other hand, the incongruent agreement of numerals with the underlying singulars of cooccuring plural nouns is definitely extrinsically ordered.