Early observations of weight or heaviness have been credited to a rhythmical feel that unconsciously takes shape in languages, that is, the tendency of growth, to go from shorter to longer elements within a phrase.
[3] Other observations on heaviness include: Examples 1a, 2a, and 3a all show canonical order whereas 1b, 2b, 3b show the NP shifted to the right of its canonical position: If a constituent is not considered 'heavy' or 'complex', the shift would not make grammatical sense or would be considered awkward to a native speaker of English, e.g.
Particles in Japanese encode syntactic functions, marking the relationship of the subject and object (NP) to the verb.
The entire constituent my rich uncle from Detroit has 'shifted' from its position as a complement to the verb to an adjunct of the VP.
The study focused on whether speakers and writers produce the word of heavy NP shift for their own benefit, or if they take into account the needs of the listener or reader.
In this study, two verb classes were compared to test the choice of early and late commitment (points when the speaker has 'committed' themselves to producing a VP immediately followed by NP and PP constituents).
The study examined transitive verbs, which require an NP object (e.g. bring, carry, make, put, etc.)
and prepositional or intransitive verbs that do not require an NP object (e.g. add, build, call, draw, leave, etc.).
After analyzing written and spoken corpus data it was found that heavy NP shift is more common with intransitive verbs.
This suggests using heavy NP shift word order with intransitive verbs allows the producer more time to decide whether they will include a direct object or not.