Tense-less Sentences in Japanese

A particle-less sentence in Japanese can refer to an event that occurred in the past. One might read in a newspaper headline: 株価下落する.

This, compared to 株価が下落する, is a reference to a past event. One typically reads in newspaper what happened the day before. It is the absence of the subject particle that keeps the sentence from referring to the present as verbs in the ru-form usually do.

I have been thinking about this off and on and come to realise that generative grammar has a great answer. X-bar theory, a sub-branch of the theoretical linguistics, holds that if and only if a verb is coded with a tense, then it can mark the subject noun with nominative (subject being a function vs. nominative being a manifest/morphological case marking).

Now, we know as an observed datum that 株価下落する sentence does not refer to the present. So, according to X-bar theory (or more specifically, the one that concerns inflectional phrases) the verb 下落する is not coded with a tense. The absence of the present, which is a tense, makes it impossible for the usual subject marker -ga to come into the scene.

A verb can also have an aspect besides a tense. Usually ru-forms are coded with the perfective aspect and the non-past tense. In this example sentence, we have no reason to consider that the apsect is taken away from the verb even if it is not marked with a tense. 下落する, therefore, is a tenseless reference of a perfective event. This is close enough to be used in place of the past in newspapers. The difference between the tenseless perfective and the past is that the former cannot accompany a specific reference of time: while 三日後に株価が下落する (non-past: typically, future interpretation) and 三日前に株価が下落した (past) are okay, *三日後に株価下落する and *三日前に株価下落する are ungrammatical. This further corroborates that the type of particle-less sentences we have discussed is tenseless — tense elements supplied from an adverbial component of the sentence are rejected because it is not amenable with the verb.