In free word-order languages like Japanese, however, syntactic flexibility is much more common. This difference between free and fixed word-order languages has important implications for theories of sentence production.
Most theories distinguish functional from positional processing.
This is the job of positional processing, to determine the sequence of words and phrases in a sentence. In fixed word-order languages, determining the functional role and the positional role of a given noun is often the same thing, since something like subject is necessarily defined by its position in a sentence. Hiromi Yoshita, as part of her honors thesis for the Department of Psychology, explored some beginning questions with Japanese sentence production. Their methodology involved having subjects produce sentences in response to a question that would set up one noun in the sentence as given. An example from Bock and Irwin is illustrated below.