There is a sense in which both interrogative and negative forms carry an inherent polar emphasis. This arises from the fact that the simple tense declarative and positive forms which are their paradigmatic counterparts carry no separate functional marker, and are characterised by the absence of any such element in their structures (the finite being expressed as a main verb inflexion). The addition of the operator element in the interrogative and negative forms thus attracts to itself an inevitable concentration of attention simply by virtue of being an additional structural component. Thus an element of emphasis is inherent in the structural composition of these systems.

Inherent polar emphasis also arises from the fact that in practice statements normally have positive polarity unless there is a good reason for this to be otherwise. This relates to normal expectations, and positive polarity is the norm against which negative polarity is contrasted. Consider the likely uses of the following:-

(ii) It isn't raining.

Here, statement (i) is likely to be uttered if the event "raining" should occur. But we should make statement (ii) only in contrast to the event referred to in (i) having already occurred or been expected to occur. Thus it is only with reference to the expectation norm of positive polarity that negative polarity can be expressed. If the event has not occurred or been expected to occur, then statement (ii) is redundant and without meaning.

Against this background of inherent structural emphasis which is as it were already "designed" into the system as an inbuilt feature, there is a further system of emphasis which supplies additional patterns of stress and contrast. This operates either by means of intonation or by use of the operator DO.

Let us consider first how intonation enables us to structure stress in the verbal group. A neutral stress pattern for positive polarity will place the point of prominence on the main verb as follows:-

In the case of negative polarity, however, the tonal prominence shifts either to the auxiliary verb to which the negative particle is attached in the contracted form, or to the particle itself when not contracted, thus reflecting and underlining the inherent structural emphasis of this form.

Although in the system of polarity it is negative polarity which is contrasted with positive polarity, a contrast which is emphasised through normal patterns of intonational prominence, it is also possible for positive polarity to be emphasised in contrast with negative polarity. This may be realised by means of intonation and structural form, and involves shifting prominence from the main verb to the auxiliary. Auxiliaries may therefore not be contracted when they carry the tonal prominence in this way.

When the auxilairy verbs BE and HAVE occur as operators, the system of emphasis at this level thus contrasts contracted with non-contracted structures in the verbal group. In positive polarity this occurs at initial position in the verbal group - whether the auxiliary operator is contracted or not. The uncontracted operator is emphasised.

Linked with the emphatic function of intonation there is also the system of positive polarity emphasis using the operator DO. This occurs only in simple tense verbal groups which have no other auxiliary verb. We saw in the case of complex verbal groups that tonal emphasis falls on the initial operator in the group. The function of the verb DO for simple tense groups which have no operator is thus to be the focus for the tonal prominence which it carries, thereby providing an emphatic contrast with the neutral form.