x1=v1=s1 is a word/set of words (able to be) recalled by x2=s2 about subject x3=s3; x1 is the vocabulary retrieved by x2.
From valsi selmo'i, 'word(s)-remembered'. An attempt at translating the English word 'vocabulary'. Pedantically, refers only to the words actually remembered, rather than those that are merely retrievable. vlamojyzilcmi ('word-remember-set') is a potentially more accurate translation of the English word.