Syntactics, or syntax, is concerned with the way sentences are constructed from smaller parts, such as words and phrases. Two steps can be distinguished in the study of syntactics. The first step is to identify different types of units in the stream of speech and writing. In natural languages, such units include sentences, phrases, and words. In artificial languages, lexemes, tokens, and formulas are usually found among the basic units. The second step is to analyse how these units build up larger patterns, and in particular to find general rules that govern the construction of sentences. [1]
This can be broken down into constituents, which are a group of words that are organized as a unit, and the organization of those constituents. They are organized in a hierarchical structure, by embedding inside one another to form larger constituents.
The syntactic hierarchy (from smaller to larger units) is as follows:
- Morpheme
- Word
- Phrase
- Phase
- Sentence (clause)
- Text
The domain of a phase is not universally recognized, and only appears in generative works from the '90.
The term morpho-syntactic hierarchy is a synonym.