So we got exactly one new word of Adûnaic in Nature of Middle-earth: Adûnayân, that's what Adûnaic called itself, and I am forced to discard my previous hypothesis that its name was Adûnaiyê, analogous to Nimriyê 'Elvish' in the Notion Club Papers.
Its structure is difficult to interpret. My first association was the other name, Yozâyan 'Land of Gift', but that is based on an attested noun zâyan, pl. zâin 'land', which cannot be present here (note the different place of the long vowel, though with Tolkien it is not always significant). The NCP have also provided us with an agental suffix -ân that produced nouns like magân 'maker'. But that would suggest an interpretation of Adûnayân as 'Westerner' or in fact 'Westron', and I am not sure whether this reading holds.
But then, we have cases like abâr 'strength, endurance' > abrazân ' steadfast, faithful; Voronwe'. Can we draw an analogy? The basic element of Adûnayân is no doubt Adûna ' a Númenórean', shall we simply add a glide consonant y + -ân', following the structore of -ada in azûlada > -yada in avalôiyada to avoid a vowel cluster?
But then, we also have got from the NCP the possessive prefix an-, included, among other examples, in an-Adûn 'of the West'. Maybe Tolkien decided in the third phase of Adûnaic, that in Words of Westernesse I had labelled a-Adûnaic for reference purposes, to make it a lenghtened suffix: *adûnân. In that case, Adûnayân would simply mean '[Language] of the Númenórean(s)': Adûna + y + poss. suff.
Anyway, it's time for an update to Words of Westernesse.
