Thank you for this e-lecture which is valuable for my studies in linguitics. However I have got a concern: Can vagueness be considered as a discursive strategy? To what extent, if that's the case?
That is my take. Many of these examples are vague because either: it was pulled from a well constructed sentence and so is missing pertinent information, pulled from a poorly constructed sentence, the meaning was specifically withheld for some purpose (to add intrigue or deception), or the words are intentionally created vague to provide more elasticity to the language. I still haven't seen an example of this vagueness which seems to be one which can't be overcome with effort. Having issues with classifying height? Look at the average for a region and compare. Height would then be relative, region to region. If that is not acceptable, take the average height of all regions. Point being, there is a solution. I hope you are still active on youtube :)