The structural typology I provided above must be complemented by a functional typology. Many attempts have been made: ``lyrical soliloquy'', the ``soliloquy of reflection'', the ``soliloquy of decision'', the ``soliloquy of planning'' and the ``soliloquy of conflict''. The problem with these attempts is that they lack a clear-cut distinction and the number of categories can be expanded at will. I will describe Pfister's typology of soliloquies. His system is constructed according to one criterion, the relationship between speech and action.
The main distinction is that between actional and non-actional soliloquies. The actional soliloquy is in itself an act which alters the situation. The speaker reflects on different possibilities for action and then selects one.
Non-actional soliloquies do not change the dramatic situation and contain elements of epic communication structures. The epic effect increases in proportion to both the distance between the commentary and the dramatic situation and, between the speaker and his active role within the plot.
There are two kinds of non-actional soliloquies: the informative or expository and the commentative, the audience must first be informed of particular events and situations. The commentative soliloquy describes an event or situation with which the audience is already familiar, and it is interpreted subjectively from that figure's perspective.
In extreme cases, the result might be a speech ex persona in which the commentary goes beyond the figure's level of awareness and develops into a commentary that can be detached from the speaker, to convey, in epic form, the intended reception-perspective. The final part of the first ballad is an example of this, where Todd seemingly rises from the grave. In such cases, the soliloquy assumes the function of the mediating commentary in much the same way as does the chorus in the classical drama.
Poor Thing is a good example of this. Actional, informative and commentatative soliloquies are ideal abstractions.