The court will hold a hearing on the issue.
The slayings shocked the sleepy town.
The running of the bulls is held annually in Pamplona.
His fiery sermons attracted a strong following.
Famous sayings take on a life of their own.

As a matter of English grammar, what are the “-ing” words in these sentences? I genuinely do not know.

The most boring possibility is that they’re just nouns related to verbs, and it’s just an accident of English etymology that they end in “-ing.” These words seem like they’re part of a family formed in a fairly similar way, though, so I’m hoping there’s something more to it than that.

They clearly function as nouns; they’re clearly created from verbs. We ordinarily call nouns and adjectives created from verbs “verbals.” In my eighth grade grammar class, we were taught that there are three kinds of verbals in English: gerunds, participles, and infinitives. We can rule out infinitives, as English infinitives are preceded by the particle “to.”

Participles are normally adjectives (as in “the running refrigerator”), so to function as nouns, the “-ing” words above would have to be adjectives functioning as substantives. In English it’s possible to have an implied generic noun and thereby effectively turn an adjective modifying that noun into a noun itself. “Give me your tired, your poor” contains two adjectives that are doing the work of nouns. This construction arguably works in a fairly awkward way for “following,” above, but clearly fails for the other four. All five of the sentences would get a (*) next to them in a lingustics paper if “one” or “ones” were inserted after the “-ing” word.

Let’s try gerunds, then. Gerunds — as in “Running is fun.” — ordinarily refer only to the activity of the verb itself. That activity can be restricted by qualifying it with appropriate adjective phrases (e.g. “Competing in the Olympics is every athlete’s dream.”) But the “-ing” words above seem to refer to something even more specific. It’s an activity reified into a particular thing or things. The “hearing” exists at a particular point in time. You can count the “slayings.” I’m just not used to seeing English gerunds thrown around like that.

That would seem to leave us out of options—unless we can find another type of verbal. In Latin, verbs can be formed into infinitives, participles, gerunds, … and supines. The Latin supine is an extraordinarily restricted construction—the nouns thereby formed can only be used in two out of the seven grammatical cases. The most common use of the supine is actually where English would use an infinitive.

The one thread that seems potentially worth of pulling on is that supines also, in their ablative form, lead to constructions such as mirabile dictu, “strange to say.” The ablative case is used almost exclusively in Latin for prepositional phrases and phrases that, how can I put this, feel prepositional. (I’m sorry for my inarticulate grunting. After a few years, the cases become as much intuitions as logical rules. I could never explain in words why a double dative or a partitive genitive uses the case it does—it’s just that any other case would be wrong.) In any event, to capture the proper ablative flavor of dictu, I’d rather translate it as “strange with respect to saying.” That still doesn’t quite get us to the “-ing” words above, but perhaps “strange with respect to the saying” does.

So, perhaps by exceedingly strained analogy, we can think of the “-ing” words above as supines. They represent the action work of a verb condensed into a specific reified thing, which thing can then be slung around and inflected just like any other English thing word—a.k.a noun.

Or perhaps sometmes a noun is just a noun and well enough should be left alone.