A root is a fundamental minimal unit in words. Some languages do not allow their roots to appear on their own, as in the Semitic languages where roots consist of consonant clusters that become stems or words by virtue of vowel insertion. Other languages appear to allow roots to surface without any additional morphology, as in English car. Roots are typically distinguished from affixes in that affixes need a host, although this varies within different theories. Traditionally roots have belonged to the domain of morphology. More recently, though, new theories have emerged according to which words are decomposed and subject to the same principles as sentences. That makes roots a fundamental building block of sentences, unlike words. Contemporary syntactic theories of roots hold that they have little if any grammatical information, which raises the question of how they acquire their seemingly grammatical properties. A central issue has revolved around whether roots have a lexical category inherently or whether they are given a lexical category in some other way. Two main theories are distributed morphology and the exoskeletal approach to grammar. The former holds that roots merge with categorizers in the grammar: a root combined with a nominal categorizer becomes a noun, and a root combined with a verbal categorizer becomes a verb. On the latter approach, it is argued that roots are inserted into syntactic structures which carry the relevant category, meaning that the syntactic environment is created before roots are inserted into the structure. The two views make different predictions and differ in particular in their view of the status of empty categorizers.
Željko Bošković and Troy Messick
Economy considerations have always played an important role in the generative theory of grammar. They are particularly prominent in the most recent instantiation of this approach, the Minimalist Program, which explores the possibility that Universal Grammar is an optimal way of satisfying requirements that are imposed on the language faculty by the external systems that interface with the language faculty which is also characterized by optimal, computationally efficient design. In this respect, the operations of the computational system that produce linguistic expressions must be optimal in that they must satisfy general considerations of simplicity and efficient design. Simply put, the guiding principles here are (a) do something only if you need to and (b) if you do need to, do it in the most economical/efficient way. These considerations ban superfluous steps in derivations and superfluous symbols in representations. Under economy guidelines, movement takes place only when there is a need for it (with both syntactic and semantic considerations playing a role here), and when it does take place, it takes place in the most economical way: it is as short as possible and carries as little material as possible. Furthermore, economy is evaluated locally, on the basis of immediately available structure. The locality of syntactic dependencies is also enforced by minimal search and by limiting the number of syntactic objects and the amount of structure accessible in the derivation. This is achieved by transferring parts of syntactic structure to the interfaces during the derivation, the transferred parts not being accessible for further syntactic operations.