Interdisciplinary Information Sciences Vol. 24, No. 2 (2018) 91–179 #Graduate School of Information Sciences, Tohoku University ISSN 1340-9050 print/1347-6157 online DOI 10.4036/iis.2018.R.01 Diachronic Syntactic Change and Language Acquisition: A View from Nominative/Genitive Conversion in Japanese Yoshiki OGAWAÃ Graduate School of Information Sciences, Tohoku University, Sendai 980-8579, Japan Harada (1971) argued some forty five years ago that the Japanese phenomenon called ‘‘Nominative/Genitive Conversion’’ (NGC) was undergoing a syntactic change, which was detected as idiolectal variations. Synchronically, Miyagawa (2011) argues that the NGC is not a free alternation but that more stative predicates are more likely to accept a Genitive subject. However, no one has ever proposed an argument that bridges the synchronic preference for ‘‘stativity’’ of the NGC and its diachronic syntactic change, which is characterized as ‘‘stativization.’’ In this article, we will show that the diachronic syntactic change has been in progress at least for the last 100 years. It will be shown that the semantic ‘‘stativization’’ is an epiphenomenon of the syntactic microparametric change which we refer to as ‘‘clause shrinking,’’ or a change in the syntactic size of the Genitive Subject Clause (GSC) from CP to TP to vP to VP/AP. Moreover, we will explain how such a drastic language change have actually influenced language acquisition for children who were born in different time periods, by integrating Kayne’s (2000) microparametric syntax, Snyder’s (2017) theory of competition between incompatible constructions, Lightfoot and Westergard’s (2009) micro-cue analysis of language acquisition, Manzini and Wexler’s (1987) Subset Principle, and Bosˇkovic´ (1997) Minimal Structure Principle. KEYWORDS: Nominative/Genitive Conversion, Japanese, diachronic change, frequency change, language acquisition, microparametric syntax, corpus 1. Introduction In the modern Japanese, as well as in all the other Nominative–Accusative languages in the world, the subject of a clause is usually marked for the Nominative Case morphology ga. In Japanese, however, especially in an adnominal clause, there is another option of morphological Case-marking such that the subject is marked for the Genitive Case no, as in (1): (1) a. Taro-ga sun-dei-ru mati Taro-Nom live-Prof-Nonpast town ‘the town where Taro is living’ b. Taro-no sun-dei-ru mati Taro-Gen live-Prof-Nonpast town ‘the town where Taro is living’ In generative linguistics, this phenomenon has usually been referred to as the ‘‘Nominative/Genitive Conversion’’ or ‘‘ Ga/No Conversion,’’ and a pile of synchronic analyses have been proposed to account for why the Case conversion is possible in some syntactic environments but not in others (Harada (1971, 1976); Nakai (1980); Miyagawa (1993, 2011, 2013); Watanabe (1997); Ochi (2001); Hiraiwa (2002, 2005), Maki and Uchiori (2008); among others), but almost nothing has been understood about how the phenomenon is related to the Case system of a classical Japanese (which is totally different from the current one, as shown below), whether there is an ongoing change in the applicability of the syntactic phenomenon, and if any, how such a language change can be explained under the parametric syntax, which began with the advent of the Principles and Parameters Theory (Chomsky 1981), since it is only Harada (1971, 1976) who discussed the idiolectal variation about the (im)possibility of Ga/No Conversion in certain constructions. Nambu (2007, 2014) presents a result of a corpus search which shows the existence of decline in the frequency of Genitive subject clauses in the last 100 years, though he presents no investigation of construction-by-construction diachronic change in the NGC or no syntactic explanation of any diachronic change. In this article, we will first show a result of my own large-scale corpus-based study which shows that the syntactic subconstructions in which a Genitive subject clause (henceforth, GSC) can be licensed have become more and more narrowed even in the last 100 years, and there are at least two more dialects than what Harada (1971) identified about Received September 2, 2018; Accepted November 30, 2018 ÃCorresponding author. E-mail: [email protected] 92 OGAWA the extent to which the GSC can be licensed. Since his identified dialects are called Dialects A and B, two more dialects will be referred to as Dialects C and D. We will argue that the Dialect A, which is directly linked to the grammar of the classical Japanese, has almost completely disappeared, and the remaining three dialects have been spread over three different age groups who are alive now, as of the years 2016–2018, and that the microparametric change among the four dialects has been triggered by different micro-cues available for children in different time periods. In discussing the issue of how language change is related to language acquisition, we will resort to Kayne’s (2001) microparametric syntax of language variation and Lightfoot and Westergaard’s (2007) micro-cue analysis about the relation between language change and language acquisition, as well as Manzini and Wexler’s (1987) Subset Principle and Westergaard’s (2014) economy principle of children’s production as one of the third factors (Chomsky (2005)). This article is organized as follows: in Sect. 2, we will argue how the language change in Nominative/Genitive Conversion (henceforth, NGC) can be assimilated or analogized to a well-known phenomenon of language change, and review the previous generative syntactic approaches to the language change, its acquisition, and relevant parametric change, and summarize what problems have been solved in the course. In Sect. 3, we will show from investigation of corpora how the frequency and distribution of Nominative subject adnominal clauses (NSC) and GSCs have changed from the old Japanese and to the present. In Sect. 4, we will argue that a change in the frequency and distribution of Nominative and Genitive subjects is not semantic but syntactic in nature, and make a brief review of previous analyses of the GSCs and/or the NGC in Japanese, all of which are synchronic analyses, except for Harada (1971, 1976). In Sect. 5, a new analysis of the diachronic change in the syntactic environments of the Genitive Case assignment is presented. More specifically, I propose that the GSC at the complement of the functional category D as a Genitive Case licensor has been shrinking from CP to TP to vP to VP/AP in the last 100 years or so, while the NSC has been CP throughout the history. In Sect. 6, we will argue how successfully the four different dialects can be learned by a child in different time periods and how language can change, where the Subset Principle and/or a kind of economy principle play a role. In Sect. 7, we will discuss how successfully generative syntax can explain any gradual language change, and push away critics against generative syntax from historical linguists. Section 8 is a conclusion. 2. Microparametric Syntax: How to Apply It to Diachronic Change Genitive Case is usually used for marking the ‘‘subject’’ of a NP, where the notion of ‘‘subject’’ is loosely defined, so as to cover not only the so-called ‘‘subject’’ of a derived nominal but also any element having some relation R to the head of a NP. Relatedly, the Genitive Case in Japanese is realized with the Genitive Case morphology no, whether it is a NP, a PP or an adverb (or an adverbial clause) that modifies a noun, unlike in English, where only a NP can be marked for the Genitive Case and PP and adverbial clauses have the same structural relation as they are in VP, as far as Case marking is concerned: (2) a. Taro-no/Ãga hon <NP> Taro-Gen/Nom book ‘Taro’s book’ b. Taro-kara-no tegami <PP>1 Taro-from-Gen letter ‘a letter from Taro’ c. Taro-ga kita-ato-no sawagi <adverbial clause> Taro-Nom came-after-Gen fuss ‘the fuss after Taro came’ Since the advent of generative syntax, it has tacitly been assumed that Nominative Case for the clausal subject is 1An anonymous review wonders if this instance of no is not a Genitive Case but a copula, which is sometimes spelled out as no in Japanese. Here too, one can say that tegami-wa Taro-kara da ‘The letter is from Taro.’ However, we can reject this possibility for two reasons: first, the fact that a PP in Japanese can be marked by no is part of a broader generalization in Japanese that any vategory, whether a NP or a non-NP (such as AdvP, CP), can be marked by no, as in (i): (i) a. kanari-no simpo considerably-Gen progress ‘a considerable progress’ (cf. ÃSimpo-wa kanari da.) b. Shachoo-ga kita-to-no uwasa president-Nom came-Comp-Gen rumor ‘the rumor that the president came’ (cf. ÃUwasa-wa shachoo-ga kita to da.) Second, some PPs in Japanese, including (2b), can also be marked by Nominative Case, as in (ii): (ii) Tokyo-kara-ga yasui. Tokyo-from-Nom inexpensive ‘(a ticket) from Tokyo is inexpensinve.’ For these two reasons, we suppose that they have some nominal feature compatible with Genitive Case marking. Diachronic Syntactic Change and Language Acquisition: A View from Nominative/Genitive Conversion in Japanese 93 unmarked, with the Genitive Case marked, because the so-called Nominative/Genitive Conversion (NGC) in Japanese as in (1) can only take place in an adnominal clause and elsewhere only a Nominative Case is the only Case available for a subject (except for a few stative predicates for which a dative subject is available). But a corpus study shows that it was not until the mid of the 20th century that the subject of a finite adnominal clause came to be more frequently marked for the Nominative.