As eminent linguists like Eduard Sievers have stated, the sentence is the basic unit of language (Grundzüge der Phonetik. Leipzig 19013, para. 16). Sentences then should have primary emphasis in the historical treatment of languages. But as noted in the preface to Proto-Indo-European Syntax (PIES), no explanatory syntactic description of Proto-Indo-European had been produced by 1974. PIES was designed to remedy the situation.
The fullest treatment of Indo-European syntax is in the three volumes of Delbrück's portion of the Grundriss der vergleichenden Grammatik der indogermanischen Sprachen (1893-1900). But as noted in PIES 4, it and Hirt's two volumes of syntax (1934, 1937) concentrate on presenting the data, that is the forms and their uses. Almost amusingly Hirt stated that he didn't know what a sentence is, nor did he even want to know (1934:7). He made no effort to apply the findings of Pater Wilhelm Schmidt, presented in Die Sprachfamilien und Sprachenkreise der Erde (1926), later restated by Joseph Greenberg (1963, 19662), concerning the basic components of the sentence and their interrelationships, as based on the position of the object with regard to its governing verb. PIES set out to do so, that is, to provide a treatment of syntax that deals with the sentence, its structure and its components in their relationship to one another. In this way it is explanatory, accounting for characteristic features in relation to one another. Thus the presence of postpositions rather than prepositions, and similarly the comparative construction with standard preceding the adjective are related to the object-verb structure of the sentence. Further, the position of adjectives and genitives with regard to nouns they modify is related to the preposing of relative clauses, which in turn is related to the OV sentence structure.
Two more recent treatments must now be noted. In their large work, Indo-European and the Indo-Europeans, T. V. Gramkrelidze and V.V. Ivanov devote two chapters to syntax, the first setting the stage for its presentation and explanation. Chapter Five, "Proto-Indo-European as a language of the active type" (1995: 233-275) accounts for the "binarism of the PIE grammatical structure" in accordance with active-stative categories, treating the nominal, pronominal and verbal systems in this way. Chapter Six, "The grammatical syntagmatics of Proto-Indo-European in typological perspective" (1995: 277-303), after a brief introduction, deals in fewer than fifty pages with the "structural implications of the SOV model in the structure of the Indo-European verb" (281-303), the "structure of Indo-European nominal constructions" (303-312), and "the structure of the simple sentence in Indo-European" (313-321).
In the large Manual de Linguistica Indoeuropea I-III of Francisco R. Adrados and colleagues, Julia Mendoza is credited as author of Part 4: Syntax (III: 143-246). It consists of three chapters: I. "Reconstruction of Syntax. History and Methodology" (143-154); II. "The Simple Sentence" (155-200); III. "Parataxis and Hypotaxis" (201-246). The large pages of the book permit an extensive description. While noting briefly treatment of syntax with reference to OV/VO structure, Mendoza does not deal with it at length. In other respects, like PIES her account is descriptive. In view of her thorough coverage of the sentence, its components, intonation, verbal and nominal modifiers, as well as types of clauses, her work would be widely welcomed if made available in English translation.
For fuller understanding of the syntactic structure of Proto-Indo-European syntax, especially irregularities, greater accounting made in specific articles may be consulted, such as my "Agreement Languages," The Twenty-Second Lacus Forum 1995, pp. 19-34, and "Problems in Proto-Indo-European Grammar: Residues from Pre-Indo-European Active Structure," General Linguistics 29: 228-246, both with extensive references. The problem is further addressed by Pre-Indo-European of 2002, which provides an explanatory syntax of the earlier language in the period from 8000-5000 B.C. Yet a comprehensive work comparable to Delbrück's though concentrating on the structure of the sentence with explanatory discussion would now be highly welcome.Winfred P. Lehmann