According to Hale, the relatively unconstrained manner in which words are ordered within the sentence is due to the way in which the projection principle acts in non-configurational languages. Hale's Configurationality Parameter (CP) holds that, in non-configurational languages, the projection principle holds of only lexical structure (LS). This is in contrast to configurational languages, where CP states that the projection principle holds of both phrasal structure (PS) and lexical structure. According to Hale, it is the lack of relation between lexical structure (LS) and phrase structure (PS) of sentences in Warlpiri that permits the three characteristics of non-configurationality to be present: