... that we owe several Western and Theyalan words to the wereducks?
Take sordid, for example. There are some that claim this word has a Western etymology, coming via the Seshnegi sordide from some ancient perfect tongue in the Land of Logic, or whatever those weirdos believe. Boulderdash!
As any good Grey Sage will tell you, the wereducks (and their cousins, the keets) tend to describe groupings of themselves using rather colourful collective nouns. Unfortunately, this is particularly true in the case of those given to criminality.
Many of the durulz of Dragon Pass and Maniria are of such bloodlines that they favour the collective noun sord. Originally, the adjective sordid--actually coined by God Learners in Slontan, that meeting ground of Western and Theyalan--just referred to anything connected with such a group and lacked any pejorative sense; sordid and sordide were used simply to mean (of a group of) fowl.
Only later did the the sord became so associated with thievery, brigandage and general purulence, that it took on its current meaning. In some Theyalan dialects this reflected upon the character of the durulz themselves, such that in certain useages fowl degenerated into the present spelling and meaning, foul, likewise embraced in the West.
Another example is the Theyalan noun sluggard, typically used to describe someone or thing that is habitually sluggish--slow, lazy and disinclined to work. There are fanciful ideas that, in Old Heortling, it derived from slug, meaning slow and heavy, and slothfulness personified--and that only later was slug used to define those poor molluscs. This is, unfortunately, incorrect.
Slug (usually pronounced 'szhlugg') is a durulz word and has always been used to define said molluscs. The slow characterisation derived from such, and not vice versa. Sluggard is actually a contraction of 'slug-herd(er)', i.e. that durulz that makes his slow, patient living herding the monstrous slugs that thrive by the Marsh. In durulz, there is the cognate snallard, which naturally derives from 'snail-herd(er)'. Used together, in sluggardly and snallardly, they form a phrase commonly used to indicate considerable slowness of thought or action.