I will represent the dual structure of natural language expressions by means of two-sided diagrams such as (6), in which the upper trees describe the internal structure of each word, and the lower tree the syntactic structure of the example. The dashed lines connecting the two structures do not indicate structural relationships, but rather the association of elements of the structures given by quite separate systems, in this case a simple and allowable association.
- Sadock (2004), Pag. 329