I'm planning to join the metaphilosophical fray over what counts as a merely verbal dispute. My first thought is that what counts as a merely verbal dispute is likely to depend to a fair extent on what the parties to the dispute are interested in. One obvious way it looks like this can happen is that various prima facie substantive-sounding disputes can turn out to be merely terminological if the parties are self-consciously interested in settling a point of terminology. But this isn't the only way.
For instance, consider disputants A (an externalist) and B (an internalist), who argue as follows:
A: "We both know that there is an external world."
B: "No-one knows that there is an external world."
Suppose A and B agree that they each stand in relation E to the proposition There exists an external world, where E is the relation that A, being an externalist, takes to be sufficient for knowledge. And they also agree that nobody stands in relation I to that proposition, where I is the relation that B, being an internalist, takes to be necessary for knowledge.
Now suppose that when they realize they agree in these ways, they find that this enables them to resolve all the points they were interested in. Then we might be tempted to say that their original dispute was merely a verbal dispute about 'knows'. But in fact things aren't quite that simple - we want to allow that two people could resolve a substantive dispute about knowledge by thinking about the E and I facts, even where the original dispute was a substantive dispute about the knowledge facts (as opposed to the E and I facts) and not merely a verbal dispute about 'knows'. For instance, it could be that thinking about the E and I facts helps one of them to notice the facts about the knowledge relevant for resolving their dispute. Instead, I think that being resolvable in this way is a symptom of a merely verbal dispute. It is a symptom because it (fallibly) indicates that they never really diagreed about anything they were interested in, which I think is crucial for whether their dispute was merely verbal. (That's not supposed to be a criterion by itself either, but it's closer.)
But if noticing these points of agreement does not resolve their dispute (and the same goes for any other agreements of a similar kind that they may have), then it's tempting to say their dispute is not merely verbal but concerns a substantive point about knowledge. And that's going to be because this is evidence that what they're interested in is the facts about knowledge, and not just the E and I facts (or whatever).
In fact, however, there's something appealing about the thought that their dispute might still be merely verbal even if they are interested in knowledge for its own sake. For if there are no knowledge facts as distinct from the facts about E and I, then there is nothing substantive for their dispute to be about. So their dispute - if it is to have any point at all - must boil down to a disgreement about whether 'knowledge' tracks (and/or should track) E or I. If this is right, the interests of the disputants don't always settle whether the dispute is merely verbal. Still, they surely have an impact in many cases.