The source text on which the translator works is a material object in which the TRANSITIVITY choices have already been made and have been realized through the syntactic and lexical systems of the language in which it is written. The text consists, therefore, of clauses which are explicitly present and propositions which are only present in an implicit sense.

In addition, although there is a mapping of propositional structure onto clause structure, there is no necessary one-to-one match between Actors, Processes, Goals and Circumstances on the one hand and Subjects, Predicators, Complements and Adjuncts on the other. Such 'mismatches', both within and between languages, are of considerable interest to the translator, since it is by recognizing them and, for example, inferring underlying propositional structure where elements of it are 'missing' in the surface syntactic structure, that the translator 'makes sense'of the source text; the prime prerequisite for translating it.

Languages differ considerably in the extent to which Participant and Process relationships are actually realized in their syntax and this constitutes a substantial problem for the translator.

This might be illustrated by taking Relational and Existential Processes as an example and comparing their realization in a number of languages, basing our discussion on the following six sentences:

1b A tiger is an animal

1b A tiger is fierce

2a There is a tiger

2b There are tigers in Bengal

3a The tracks are a tiger's

30 Tigers have stripes

Examples 1–3 illustrate the three major types of relational process; intensive, circumstantial and possessive. The distinction between them is easily stated in terms of the relationship between the participants in the process

(1) intensive; x is a

(2) circumstantial; x is at a

(3) possessive; x has a

and, within each, two types of participant relationship;

(a) identifying: identified + identifier, where 'x' and 'a' are reversible, since the relationship between them is one of equation and

(b) attributive: carrier + attribute, where 'x' and 'a' are not reversible.

We can comment on each of the six examples in turn:

1. Intensive

1a A tiger is an animal; the equation of tiger and animal allows two realizations of the relationship in terms of either

(i) class-membership: 'a tiger is an animal' (belongs to the class animal) or

(ii) example: 'that is a tiger' (an example of a tiger).

1b A tiger is fierce; the lack of equation between 'tiger' and 'fierce' indicates that it is the attributes or characteristics of the entity that are being referred to.

2. Circumstantial

The circumstantial differs from the intensive (and, as we shall see, the possessive) in that the relationship is not between the entity and other entities but between the entity and its setting.

2a There is a tiger. a tiger is located at a particular point in space and identified by being there.

2b There are tigers in Bengal: an attribute, but not a defining characteristic, of tigers is to be located in Bengal.