Modal verbs take on new meanings when when used in speech acts. Speech acts go beyond the mere exchange of information and have pragmatic implications for the speaker or addressee or the relation between them. 

The expression of ‘will’ may become  a ‘commitment’ even when directed by the speaker at him-/herself:

'Will’ may be projected on an addressee, as in the case of a sculptor about to destroy a bust he has made in anger:

Wil is used in a polite request, as in (14a), mitigated by the negative without a change of meaning, as in (14b).

If a host insists on the ‘possibility’ of extending a visit, this may count as an ‘invitation’:

Informing the addressee that there is no objection to an action envisaged by him/her is tantamount to granting ‘permission’ (16a) or may even be a threat (16b):

By suggesting a certain readiness to perform an action the speaker may be offering to perform the action:

In the context of a meal, a question such as the following is, through a process of inferencing, conventionally understood as a request.

Kon is used instead of kan to make a suggestion (19a), offer (19b) or request (19c) sound more tentative:

Sham permission may be employed to express praise:

An 'obligation' ascribed by a speaker to an addressee, amounts to a request. In speech acts, moet is therefore usually a directive, an act whereby the speaker attempts to get the hearer to do something(Archer, Aijmer and Wichman 2012:39).  

In (22), the speaker applies the directive to herself:

If the obligation is explicitly removed, prohibition may result, as in (23). As a speech act, a prohibitive remains a request or directive.

As the conventionalised form of the prohibitive in Afrikaans (see moet under Root meanings), the illocutive force of moenie equals that of an imperative:

If the speaker wishes to cancel or relax the necessity of the action, hoef ... te may be used, as in:

A confession may be mitigated by feigning obligation:

A commissive is a speech act in which the speaker commits him/herself to do some future act(Archer, Aijmer and Wichman 2012:39). This may have its origin in an intention directed at the addressee, and have the force of a promise:

When the prediction is made directly applicable to the addressee instead, thereby raising its status to that of a faît accompli in the addressee’s future, this may result in a directive of considerable force. The speaker’s intention is emphasized prosodically:

An unlikely outcome is the vehicle for indignation in:

To mitigate requests or for the sake of politeness, questions containing sal or its preterite form sou are used. The addressee is given time to consider the request, hence the future projection of sal, while sou allows the addressee even more freedom by making the request more tentative. The addressee is afforded an opportunity to make a prediction of the speaker come true. Further mitigation may be introduced by appealing to the addressee’s ability (by kan/kon) to fulfill the request. This may be accompanied by non-verbs, such as the particle of polite request, asseblief please, an emotive epithet such as ou old and the – perhaps slightly ironical – use of the diminutive, as in gunsie favour.DIM:

Sou is used in a slightly ironical/emotive (disgruntled) way in a fixed expression:

Wishes are expressed somewhat formally by mag, in a formulaic construction requiring inversion, and only have the force of a wish when directed at an addressee:

In informal interaction wishes are expressed by means of declaratives with moet must, which derive their force from the urgency of ‘obligation’:

The wish in the following derives its urgency from the inherent ‘prohibition’: