Let us assume, for instance, that in a contour describable in terms of the succession of levels 2-3-2, level 3 is replaced by level 1. The peak of the curve will than be replaced by a trough. Level 3, which, all by itself, implied a rise, will be replaced by level 1, which, all by itself too, implies a dip. This shows that every one of successive level is indicative of one of the specific directions assumed by the melodic curve. Now, each of these successive directions is contributing something to the significance of the total contour. This contribution is additive, as is the one of a moneme to the meaning of an utterance. It is not destructive, as that of a phoneme whose presence signalises that any interference, as the meaning of the utterance, which might be drawn from the context considered without it is wrong: if, to the statement 'it is good', I add 'very', I am just adding some additional information without deleting what was previously there, but, if to the statement 'it is a roe' a add a /d/ phoneme, the statement becomes 'it is a road'; one element of information 'roe' is deleted and replaced by another one. Since a level is just a way of indicating a direction, and since every successive direction would seem to add something to the whole, it is permissible to state the value one may wish to ascribe to a given contour does not actually go beyond the values that might be attributed to every one of its successive levels. In other words, inasmuch as the contour has a bearing upon the sense of the message, it does so as the sum total of the implication contributed by every one of its components, the levels. This amounts to saying, that the relation of levels to contour is comparable with that of words to sentence, in which both words and sentence are signs with 'signifié' and 'signifiant', and basically different from that between phoneme and word, or moneme. Should we insist on identifying the items we operate with an intonational matters, with the units that are the frame of double articulation, we would have to say that levels are monemes, i.e minimal units with meaning, whereas contours are a succession of monemes.
- Martinet (1962), Pag. 36-37