*Abstract*

It would be nice to think that the meaning of a phrase is a function of the meanings of its immediate concatenated subphrases. If so, the context-free derivation of the syntactic structure of a sentence would be isomorphic to that of its semantic structure. The idea leads naturally to simultaneous derivation of syntax and semantics via a so-called synchronous context-free grammar.

Unfortunately, the widespread existence of apparently noncompositional
phenomena, such as quantifiers with scope, makes this impossible. What to
do? One possibility is to allow the two derivations to deviate from each
other, as has been the approach in transformational grammar models up to and including those of the minimalist program. An alternative is to allow
structures to be composed by operations other than concatenation.
(Montague, for instance, uses an operation of indexed replacement.) I will present a formalism, Joshi's tree-adjoining grammar, that augments
concatenation with a simple operation of adjunction. Synchronous
tree-adjoining grammar has the potential to allow exactly the isomorphism of derivation that other systems have given up on. It turns out that there are many arguments for such a system, some of which I will present. In so doing, I hope to interest linguists in pursuing work with this and related systems.