1. Introduction. In the general theory of linguistics, dependency theory competes for the same role as immediate-constituent (IC) theory: each formalizes a view of tactic relations among elementary units in utterances. In each theory, a finite apparatus is taken to characterize (or generate) a set of utterances that may be infinite. In addition, each theory specifies a structure, or perhaps alternative structures, for each utterance it generates.

1. In 1956, Greenberg proposed eight measures of linguistic diversity designed to determine the possibilities of communication among the population of some delimited area. Taking note of the considerable variance between areas of the world in their linguistic diversity, Greenberg's measures allow us to quantify this diversity on a continuum ranging from complete diversity, such that no two people speak a mutually intelligible language or dialect, to the other extreme, where all inhabitants share a common tongue. By going beyond mere verbal descriptions of an area's linguistic diversity, these quantitative measures enable us to correlate language usage with social, economic, political, and geographic factors.

Every Serbo-Croatian verb form consists of the constituents listed in Table l. While prefixes are optional, every verb form has a stem and at least one inflectional element. The stem consists of at least a root. Every verb paradigm has a thematic vowel in some or all of its forms, though some forms of some paradigms are without this. The remaining stem constituents are optional. The constituents always occur in the order given in Table 1.

1. Since Meyer-Lübke, it has been a commonplace of Romance phonology that Proto-Romance voiceless stop consonants have, by and large, been preserved intact in word-initial position throughout the Romance territory, whereas intervocalically they have undergone lenition, becoming voiced (and in some regions also fricative and eventually dropping). The spirants /f/ and /s/ (for which there were no voiced counterparts in Proto-Romance) have likewise become voiced intervocalically. Similarly, voiced stops are normally preserved initially, but have remained intervocalically as plosives (with the exception of /-b-/> /-v-/) only in East Romance, and have become fricatives or have dropped in the West. It is convenient to refer to these West Romance developments by the general term ‘the West Romance sound-shift’, as exemplified in Table 1 (with ERomance examples from Italian and WRomance from Provençal).

1. This paper proposes some modifications of the family-tree diagram traditionally used to indicate genetic relationships in comparative linguistics. The flaws in the traditional diagram have long been recognized; it would be difficult to improve on Bloomfield's discussion of the subject in Language §§18.9–12. Although contemporary linguists have rejected the theory on which the branching diagram was originally based, they have not taken the logical next step of trying to improve the diagram itself so as to make it compatible with the revised theory. I shall attempt to show here that it is not necessary to reject branching diagrams entirely, but that it is possible to modify the traditional diagram so that it presents a truer and clearer picture of linguistic history as it is conceived at the present time. There are probably many possible ways in which we could depict linguistic history, and I do not attempt to do justice to all possibilities here; I hope only to show some variants on the traditional diagram which may lead to a better understanding of the potential use of such devices. First, a word on the role of diagrams in historical work. The diagrams which are presented here are not intended as theoretical models, but only as visual aids. Such diagrams are at best shorthand representations of the history of a group of languages, showing in a single picture the interrelations of the whole group. The primary danger to be avoided is that of overliteral interpretation; as Bloomfield says,