Modal Verbs (Grammar for authors)

Understanding modal verbs is important in conveying conviction and commitment. They also hint at social status.

PresentNegativeSimple PastNeg. Simple Past
cancan not, cannot, can’tcouldcould not, couldn’t
maymay not, mayn’t*mightmight not, mightn’t*
shallshall not, shan’tshouldshould not, shouldn’t
willwill not, won’twouldwould not, wouldn’t
mustmust notmustmust not
have todo(es) not have tohad todid not have to
need todo(es) not need toneeded todid not need to

*Rarely used, but valid.

Generally, modals are used to indicate possibility and certainty. Modal verbs are timeless and don’t follow the usual rules of tense. “Could” can be used in present tense narratives, and “can” is also used in past tense narratives.

A character’s mentality could be flawed, so they think they know the answer. Nobody can say for sure, and most people won’t think too deeply of it.

The simple past of a modal verb (such as “could”) indicates vagueness and doubt. Vagueness is important to convey politeness and formality, a softer way to talk.

Degree of certainty, from least to most certain:

  1. may/might (least certain, most polite)
  2. could
  3. should
  4. would
  5. can
  6. shall
  7. will (most certain, most rude)

For most native-speaking authors, it’s easier to let yourself write these out naturally. However, character motivations and social interactions are one of the most important drivers in storytelling, so I believe that authors should be cognizant of the grammatical constructs used to talk about commitment.

During revision, many authors feel pressured to correct modal verbs to be in line with the overall tense of the story, but it’s more important to convey your characters’ emotional confidence than to follow a style. Modal verbs are an oddity in English tenses, so it’s fine to experiment with them.

In the first person, 6. shall is popular for vows, oaths and principles: “I shall do better.”

  • It is forceful and condescending when you tell someone else in the second-person, “You shall do this because you’re my subject.” It can be used as a joke amongst friends.

3. should is gentler than shall, but it can range from friendly advice to authoritarian suggestion, such as by mentors guiding their pupils, or to “hammer the nail that sticks out,” warning those who push the bounds of social norms before it results in disaster.

7. will is rude in the second person: “You will die.”

So there you go. That’s the purpose of modal verbs. Use them right and you seem humble and aware of your limits. Use them wrong and you’re insecure or an antagonist.

Motivation #

Motivation, politeness and emotionality is also expressed through the subjunctive tense, so you may check that out to compliment your writing.