Constant Rate Hypothesis, age-grading, and apparent time construct

University of Pennsylvania Working Papers in Linguistics Volume 9 Issue 2 Papers from NWAV 31 1-1-2003 Constant Rate Hypothesis, age-grading, and apparent time construct Kenjiro Matsuda This paper is posted at ScholarlyCommons. http://repository.upenn.edu/pwpl/vol9/iss2/11 For more information, please contact . Article 11 Constant Rate Hypothesis, age-grading, and apparent time construct This working paper is available in University of Pennsylvania Working Papers in Linguistics: http://repository.upenn.edu/pwpl/vol9/ iss2/11 Constant Rate Hypothesis, Age-grading, and the Apparent Time Construct1 Kenjiro Matsuda 1 Introduction In doing historical linguistics synchronically, sociolinguists oftentimes use what is known as the apparent time construct (Bailey et al. 1991 ). The logic behind this construct is that synchronic age differentiation reflects ongoing historical language change, so that the linguistic features oftoday's 20-year-olds are a precursor of the 40 year-olds 20 years later. Turning the diachrony of language into a synchronic matter, it enabled variationists to observe language change in progress, something that was once deemed impossible (Hockett 1958). The problem of apparent time construe~ however, is that the synchronic age differentiation is ambiguous: it could represent a case of age-grading, so that the teenagers with frequent uses of a certain form begin to use the form less as they grow past adolescence. A real-time survey of a speech community with datapoints decades apart would be the best (and only) solution to this problem. Without it, one may wonder if there is any systematic method of discerning whether a given pattern of synchronic variation is a reflection of change in progress or age-grading. This paper addresses this ·question by extending Kroch's (1989) Constant Rate Hypothesis (henceforth CRH) and explores its synchronic implications. It will be seen that the extended version of CRH logically makes a strong prediction about the diachronic status of synchronic variation. I will also show that counterexamples to the Hypothesis can be accounted for systematically. 2 What is Constant Rate Hypothesis (Kroch 1989)? Simply put, the CRH says that language change proceeds at the same speed in all linguistic contexts where it occurs. Certainly, there is a difference in the degree to which 1 A previous, larger version ofthis paper was also presented at Oxford-Kobe Linguistic Seminar on Language Change and Historical Linguistics on AprilS, 2002, and at the 99th Meeting ofVariation Theory Forum ofJapan on September 27, 2002. My cordial thanks to all the participants who raised important questions and offered their precious insights to me at the time of the presentations. Joe Emonds and Philip Spaelti deserve special thanks for their help in the final stage. The work was supported by Grant-in-Aid for Scientific Research #13410139 from Japan Society for the Promotion of Science. U Penn Working Papers in Linguistics, Volume 9.2 (2003) 124 KENJIRO MATSUDA contexts favor the innovative form, so that there are favorable contexts and not-so-favorable contexts defined by a set of linguistic features. But the speed, or the rate of replacement of the old form by the new, innovative form, is the same across all those contexts. To quote Kroch (Kroch 1989:200): ... when one grammatical option replaces another with which it is in competition across a set of linguistic contexts, the rate of replacement, properly measured, is the same in all of them. The contexts generally differ from one another at each period in the degree to which they favor the spreading form, but they do not differ in the rate at which the form spreads. Statistically speaking, then, the CRH is tantamount to saying the following: (1) CRH in statistical terms In language change, the effects of each linguistic context toward the rate of the new form are independent ofthe time and stay constant The significance of the CRH becomes clear when one considers Bailey's Wave Model (1973). The Wave Model says that language change proceeds in an S-curve fashion; it starts gradually, but suddenly, it gains momentum, running at a faster speed, imtil it peters off as it reaches the end point Furthermore, Bailey equated the favorableness of each context to the rate of change and the order of appearance of change in each context: "[W]hat is quantitatively less is slower and later; what is more is earlier and faster'' (Bailey 1973:82). Thus, the Wave Model predicts that the change proceeds fuster if a context has a large positive effect toward the new form than in other contexts with less positive effects. This is exactly where the two theories differ, and accordingly, this is one of the points where the significance of the CRH lies.2 3 Extending the CRH When Kroch proposed the CRH, his database consisted of historical data covering several centrnies. But sociolinguistically speaking, these historical changes should necessarily be reflected in synchronic age-differentiation in apparent time, so that younger speakers use more innovative forms and less conservative forms, with older speakers showing the reverse tendency. Thus, what Kroch called time then becomes age in this picture. The content of his hypothesis should still hold under this transformation, as 2 The CRH also goes against the predictions made by Anderson's Markedness Theory (Anderson 2001 ), though I will not touch on the issue here. CONSTANT RATE, AGE-GRADING, APPARENT TIME 125 virtually nothing has been changed except the scale of time and the name of the axis. At this point, the hypothesis reads as follows: (2) Extended CRH-I [ECRH-I] In language change, age and linguistic contexts are independent of each other. By taking a contraposition ofECRH-1, we would obtain (3): (3) Extended CRH-II [ECRH-II] If age and linguistic contexts are not independent of each other, the synchronic competition between two forms cannot be a reflection of language change. In other words, the ECRH-II predicts that whenever there is an interaction between age and linguistic contexts, the observed variation cannot be a case ofchange in progress. In this form, then, the ECRH-II can function as a kind of litmus test to tell whether a given case of variation is a case of language change or age-grading. Note that the ECRH-II was derived fium ECRH-1 as a contraposition, which should necessarily hold whenever ECRH-I is true, and ECRH-1 was derived by simply replacing time in CRH with age, a synchronic reflection oftime. Before looking at actual examples, let us check what kind of predictions ECRH-II makes. As we saw above, when age and linguistic context are not independent of each other (=interacting), ECRH-II predicts that it is not a change in progress, and accordingly, it can only be age-grading. But when age and linguistic contexts are independent of each other, ECRH-II does not say anything; this is because the prediction is relevant only when th (...truncated)