A purely verbal dispute is of course a dispute that arises solely from a misunderstanding about the meaning of words, where there is no difference of view as to facts between the disputants : the sort of dispute which the Scholastics sought to avoid by enforcing the maxim, Initium disputandi, definitio nominis. Logicians have held the most widely divergent views about the extent of such disputes, some maintaining, with Locke, "that the greatest part of the disputes in the world are merely verbal," others, with De Quincey, that "they have never in the whole course of their lives met with such a thing as a merely verbal dispute." The truth lies much nearer the latter extreme than the former, for when different people attach different meanings to the same term the cause of such difference of usage will almost invariably be found to be a difference of view about facts.
Peter Coffey, The Science of Logic: An Inquiry into the Principles of Accurate Thought and Scientific Method, Volume I: Conception, Judgment, and Inference, Peter Smith (New York: 1938) p. 103.
Anyone who has engaged in a significant number of arguments realizes just how much effort has to go into getting onto the same terminological page even in fairly simple arguments. But for all that, I incline to the De Quincey view myself. In general, I think, verbal disputes, to the extent that they exist, tend to be about stipulations or about classifications. But arguments about purely stipulated labels, while all about words, can generally be traced to a difference in views about how language works or about how most people will interpret it or about what would be most practically useful; and disputes about classification are never merely verbal, since they are about how facts fit with other facts. If you have a "purely verbal dispute" it always seems to be a sign that the parties involved have only argued even their own positions very superficially. If people are not on the same page, there are generally identifiable reasons why they are not; it's just that finding them requires tracing back the argument to its roots. If this weren't the case, one would expect verbal disputes to be resolvable by bare agreement to use words in the same way; but in fact the resolution of verbal disputes always requires a better understanding of the issues at stake.