Varieties of INFL: TENSE, LOCATION, and PERSON Elizabeth Ritter and Martina Wiltschko 1. Introduction The languages of the world differ in many obvious ways. But at the same time, they are also strikingly similar. Trying to understand this tension between language diversity and identity is one the most fruitful research agendas of modern linguistic theory. Our research into two languages indigenous to North America has allowed us to gain some new insight into this problem, specifically as it pertains to the nature of functional categories. Within the Chomskyan tradition, it is often taken for granted that Universal Grammar (UG) makes available a set of functional categories with fixed content. For example, adapting Pollock’s influential 1991 proposal, it is widely held that the head of the clause is a category— formerly known as INFL—which is universally associated with marking for tense. But, it has often been observed that many languages appear to lack tense marking. Thus, we find ourselves rediscovering the core observation of the American structuralists (Boas, Sapir, and Bloomfield): languages appear to differ in the categories they obligatorily need to express. We wish to show in this paper that languages do indeed differ in their categorial inventories, but at the same time we argue that this variation is constrained by a universally determined hierarchy of functional positions. That is, after careful examination of Halkomelem (Salish) and Blackfoot (Algonquian), we conclude that each of these languages appears to use different functional categories (LOCATION and PERSON, respectively), but that these categories can be analyzed as instantiating the same universal category as TENSE, namely INFL. 1 To make this case, we introduce the Parametric Substantiation Hypothesis, according to which functional categories are not uniquely associated with the same substantive content (section 2). In section 3 we argue that in Halkomelem LOCATION substantiates INFL, and in section 4 we argue that in Blackfoot PERSON substantiates INFL. We conclude in section 5 that the Parametric Substantiation Hypothesis is empirically more adequate than alternative Principles and Parameters based approaches (including the cartographic one) as an explanation for the tension between language variation and language universals. 2. Parametric substantiation as an alternative to cartography In accordance with the theme of this book, we start with a discussion of how the problem of language- specific categorial inventories presents itself within the cartographic approach (section 2.1). We point out a problem and proceed to introduce our proposal, the Parametric Substantiation Hypothesis (section 2.2). Assuming that the substantive content of INFL is not universally fixed, it is necessary to use formal diagnostics that are independent of content to identify INFL. In section 2.3, we introduce the diagnostics we have used in this research. 2.1. A problem with the cartographic approach In English, as in many other Indo-European languages, all finite clauses display an obligatory contrast in TENSE. That is, English finite verbs are marked as [+past] by means of a suffix (-ed) or an auxiliary verb (was) as illustrated in (1), or they are marked as [-past] (i.e., present) by means of a third person singular agreement suffix (-s), or a different form of the auxiliary (is), as illustrated in (2). (1) a. He walked. [+past] b. He was walking. [+past]