In context-free insertion, we find the Vocabulary entries whose category is compatible with the category of the terminal element being phonologically realized and whose features are compatible with the set of morphosyntactic features that the syntax and morphology have generated on this terminal element. As noted, this search will in some instances involve competition among different entries for the chance to spell out a particular set of features, where the entries differ only in the features they realize (that is, in their "substantive" features).
- Halle & Marantz (2004), Pag. 392