The accusative or direct object of a transitiveclause is represented in various ways in alternating constructions, most often as a prepositional phrase or PP, of which the noun phrase or NP of the one corresponds referentially to the direct object/accusative of the other. The PP may loosely relate to the proposition as one of several adjunct types, for instance a LOCATIVE, or have specific roles in relation to the main verb, such as AGENT, INSTRUMENT or SOURCE. No distinction will be made between a PP functioning as an adjunct, on the one hand, or as a complement of the verb, on the other, in the discussion to follow. The first alternation is that between a direct object and a PP headed by the prepositionvir for – a virPP in short.

The alternation of a virPP with an accusative NP, or simply appending vir to the direct object of a transitive verb under certain conditions, as in (1), is unique to Afrikaans amongst the Germanic languages, and not to be confused with the use of vir as an alternant of other prepositions in ditransitive constructions, as in (2). (See Dative and PP alternations.)

Direct Objects referring mainly to human beings and personified entities are preceded by an optional (or sometimes obligatory) vir to mark a definite constituent, such as a personal pronoun, personal name or an appellative employed as an indirect form of address, as new information in the thematic section of a proposition (see Molnárfi (1997) ). Thus, in (1), sien to see is a transitive verb, Karen has human reference and vir is obligatory after gister yesterday, which marks the beginning of the rhematic section.

Semantically, vir as used in (1) differs from other prepositions in not contributing to the meaning of the proposition, nor does it weaken transitivity, as in the case of aan on in (3b) as against (3a), i.e. while in (3a) the bone constitutes the entire goal of the chewing action, (3b) only implies that the action is directed at the bone.

Clauses containing vir also differ syntactically from those with other prepositions. Thus vir is optional in (4) and in topicalisation, as in (5), but ruled out in the subject of a passive construction, as in (6).

Other alternations between an Accusative or Direct Object and a PP are also possible. A full NP referring, for instance, to a musical instrument, as die ou viool the old violin in (7a), may be reduced to a single noun as Direct Object to express a generic sense, as in (7b).

A construction with a PP headed by aan on as in (8b) (also cf. (3b) above) may indicate that the action has only had a partial effect on the THEME, for instance a temporarily or permanently successful attempt to produce a certain effect.

The THEME of verbs with be- or ver- as prefix, as in the Accusative of (9a), may also be expressed by the PP of its prefixless variant, as in (9b).

In a number of instances there seems to be a functional switch between the role of the Accusative in constructions in which a prefixed verb alternates with its non-prefixed corollary. Thus, the alternation between ontneem deprive of and neem take might favour different roles as arguments, such as SOURCE, ons us in (10a), and THEME, al ons regte all our rights in (10b) as Direct Object. Alternations are also found where THEME alternates with EXPERIENCER, RECIPIENT and INSTRUMENT.

The following alternations will be discussed more extensively:

• (a) Accusative and Direct Object vir PP alternation
• (b) Generic Accusative and non-generic PP alternation
• (c) Telic Accusative and atelic PP alternation
• (d) Thematic Accusative and PP alternation
• (e) Accusative as THEME or SOURCE, etc.