Figure 7 Some complexity HDAs at the phonological phrase level are schematically illustrated in (29). Example (29a) illustrates a language where the word that occupies the head of phrase, say the rightmost word in a phrase, may have a degree of complexity greater than that permitted to phrase-interna words. For example, the head word, but not the dependent words, might be required, as in (29a), to consist of at least two feet; or, in the non-loca version of this HDA in (29b), the head word might be required to have at least a branching foot, i.e. a foot dominating two moras, a degree o structural complexity not required of (or allowed to) dependents: Example (29b) in fact illustrates the typical case of minimal worc requirements found in many languages, whereby a word must have ¢ certain complexity (McCarthy & Prince 1990). Such requirements are typically imposed on content words, i.e. words that can be the heads oi maximal projections; other words, such as function words, 1.e. word: belonging to certain closed classes, are often excluded from these require- ments. For example, a minimal word in Old English must have at least twe moras, a requirement that is imposed on major class words such as nouns e.g. scip ‘ship’, s@: ‘sea’, *sci, *se, verbs and adjectives (30a); however