Creating New Verbs for Tense/Viewpoint Output

I used to know this, but I’ve forgotten, and searching the Docs is difficult when you don’t already know the key phrase you’re looking for.

I’m updating one of my extensions, and I want to make the output strings compatible with the author’s tense and viewpoint changes. To do this, I need Inform to dynamically change words like “protests” to “protest” or “protested”. How do I write code that will make “protest” a new, dynamically adjustable verb?

Also, while I’m thinking of it, when an output contains both [the noun] and [the actor] in a single sentence, on what basis exactly does Inform decide whether the [are] token refers to a possibly plural noun, as opposed to a possibly plural actor?

As a final question, on what page of Writing with Inform are these details explained? I’ll probably want to cross-reference those pages in the new edition of the Handbook.

To protest is a verb.

(Chapter 14.3.)

It depends on which one was mentioned last before the [are] substitution. If you need to change it to something else you can use [regarding the noun] or [regarding the actor] or regarding a specific thing. (Chapter 14.5.)

say "'The thing with [noun] is,' [the actor] [protest], 'that [regarding the noun][they] [are] very strange.'"

To create a new verb:

To protest is a verb.
say "[We] [protest] [the noun]."

Inform conjugates the verb based on the most recently printed noun (because most of the time the subject immediately precedes the verb). If you need to override this, the text substitution [regarding the object] changes the grammatical subject without printing anything.

These details are under “Adaptive Text” in Chapter 14 of Writing with Inform.

EDIT: As Juhana said.

Just a note that Inform will conjugate almost every English verb correctly, even the irregular ones, but if it does mess up you (currently?) can specify a conjugation by hand in the old style. This isn’t in the manual anymore but you can find it here.

Thankee kindly.