In this book I will deal with certain aspects of the syntactic and semantic structure of sentences, clauses and phrases in Latin. Pragmatic aspects will be taken into account as well, though less frequently and systematically. I have decided not to provide a treatment of syntax and semantics separately because this would lead to excessive repetition. I will take syntax as my point of departure because at present there are too many uncertainties in the field of semantics and a lack of agreement among linguists about even central issues.
I will describe the structure of sentences  using a linguistic framework in which the constituent functioning as Predicate is regarded as the central element of the sentence. Examples of predicate constituents are laudat and simile est in sentences (1) and (2):
(1) pater filium laudat (`The father is praising the son')
(2) ovum ovo simile est (`One egg is similar to another one')The constituents functioning as Predicates are lexemes (or groups of lexemes)  which belong to various lexical categories. Not only may verbs function as Predicates,  as in (1), but adjectives in combination with a copula (as in (2)) and nouns in combination with a copula, as in (3), may do so as well:
(3) Alexander erat rex Macedonum  (`Alexander was king of the Macedonians')In examples (1)–(3) the other constituents of the sentence are closely related to the predicate.  In (1), for example, the noun pater fulfils the syntactic function Subject. The noun filium, on the other hand, has the syntactic function Object. Neither of these constituents (pater, filium) can be omitted without making the remaining sentence ungrammatical unless under specific contextual or situational conditions.  With the verb laudare in example (1), both constituents are non-omissible or `obligatory'.
The reason for assigning the predicate a special status is precisely that the number of obligatory constituents and the type of these constituents depend
on the specific predicate, whether a verb, adjective (plus copula) or noun (plus copula). Due to its meaning, a predicate creates a number of positions, or slots, for constituents that have a specific semantic function with respect to the Predicate. Each predicate has a particular `predicate frame' (or, under certain circumstances, a number of frames, see crosssection 2.1.1.). Thus, laudare requires two constituents, ambulare only one, inicere three:
(4) pater ambulat (`Father is out for a walk')
(5) pater hostibus timorem iniecit (`Father filled the enemies with fear')In other words: laudare is a two-place or `bivalent' verb with a `valency' of two; ambulare is a one-place or `monovalent' verb with a valency of one; and inicere, finally, is a three-place or `trivalent' verb with a valency of three.  In the same way the adjective simile in (2) is bivalent, whereas the adjective niger (`black') is monovalent. Similarly, one might call the noun laudator a two-place noun (someone is laudator of somebody or something, for example laudator temporis acti (se puero), Hor. Ars 173, `someone given to praising the time he spent (as a boy)'), The noun orator `speaker', on the other hand, is a one-place noun. [7a]
Apart from the predicate and one or more obligatory constituents sentences often contain other constituents that may be omitted without the remainder of the sentence becoming ungrammatical. Examples are interea (`in the meanwhile') and ea legione quam secum habebat (`the legion which he had with him') in example (6):
(6) interea ea legione quam secum habeat … murum … fossamque perducit (`In the meanwhile he constructed a wall and a trench with the legion he had with him', Cases. Gal. 1.8.1)Constituents like these are called `omissible' or `facultative'. Their being `facultative' does not imply, of course, that they are superfluous in the context in which they occur. In fact, they may convey quite important information concerning the Time, Place, Circumstances, Cause, Conditions, Purpose, Manner or Instrument related to the action or state denoted by the predicate and its obligatory constituents. Another group of optional constituents includes those which either convey the personal, subjective evaluation of the speaker (or writer) of the action or state (like iure `rightly', ut opinor `in my opinion') or convey a judgment about the particular wording chosen (breviter `to put it briefly'). Examples of these two types of constituents are stulte (`foolishly') in (7) and breviter in (8), respectively:
(7) num stulte anteposuit exilii libertatem domesticae servituti (`Surely it was not foolish of him to prefer the freedom of exile to slavery at home?', Cic. Tusc. 5. 109)
(8) Narbonensis provincia … amplitudine opum nulli provinciarum post-ferenda breviter que Italia verius quam provincia (`The province of
Narbonne is by the vastness of its wealth the equal of any other province and, in a word, not so much a province as a part of Italy', Plin. Nat. 3.31.
Pinkster, Harm (1942-) , Latin Syntax and Semantics [info], xii, 320 p.: ill.; 24 cm. [word count] [Pinkster].