English has a problem that most speakers do not consciously recognise and that most grammar instruction addresses inadequately: the language contains an entire grammatical system for expressing degrees of certainty, possibility, and obligation, but most users of the language deploy this system inconsistently, imprecisely, and without awareness of what their word choices are communicating to informed readers. This system is the modal verb system — the set of auxiliary verbs that includes will, would, shall, should, can, could, may, might, and must — and the precision with which a writer or speaker uses these verbs determines whether their expression of confidence, doubt, probability, and obligation lands with the intended meaning or produces a different impression from the one they intended.
The Epistemic Function of Modal Verbs
What Each Modal Actually Signals
The modal verbs of English divide into two broad categories of function: epistemic use, which expresses the speaker’s degree of certainty about the truth of a proposition, and deontic use, which expresses obligation, permission, or necessity. Both categories are relevant to professional communication, but the epistemic use is the one that most consistently produces unintended meaning in the writing of non-native speakers and even in the writing of many native speakers who have not examined their modal choices deliberately.
In epistemic use, the modal verbs are organised into a rough hierarchy of certainty. “Will” and “must” occupy the high-certainty end: “the results will be available tomorrow” expresses near-certainty about a future state, and “this must be the cause” expresses high confidence in an inference. “Should” and “ought to” occupy the moderate-certainty territory: “the results should be available tomorrow” introduces a small degree of uncertainty that “will” does not, and the distinction is meaningful to a careful reader. “May” and “might” occupy the lower certainty positions, with “might” being the weaker of the two: “this might be a contributing factor” expresses genuine uncertainty and appropriate tentativeness. “Could” adds the additional dimension of possibility-under-conditions — “this could explain the results if the initial assumption holds” — which is more conditional than either “may” or “might.”
These distinctions are not merely grammatical abstractions — they carry real communicative weight in professional contexts where the precision of epistemic language is important. A medical professional who writes “this medication will eliminate the symptoms” is making a different and much stronger claim than one who writes “this medication should significantly reduce the symptoms.” A financial analyst who writes “the market will recover by Q3” is expressing a different and more confident position than one who writes “the market may recover by Q3” or “the market might recover by Q3.” If the speaker’s actual level of certainty matches the modal they have chosen, the communication is accurate. If they have chosen a stronger modal than their certainty warrants, they are overclaiming; if they have chosen a weaker modal than their evidence supports, they are underclaiming and may appear less authoritative or decisive than the evidence would justify.
The epistemic precision of modal language has been studied in contexts far beyond formal grammar instruction, including in the design of digital products where the language used to describe probabilistic events must accurately communicate uncertainty to users making real-time decisions. A jetx casino environment — where the JetX format presents a rising multiplier that will crash at an unpredictable moment, requiring players to decide when to exit — cannot use the word “will” to describe when the crash will occur, because “will” implies certainty about a future event that is by design unpredictable. The platform’s communication about the game mechanics must use language that accurately reflects genuine uncertainty, which is a grammatically specific requirement: “the multiplier may crash at any moment” or “the multiplier might continue rising” are both more accurate than “the multiplier will crash soon,” and the distinction between these phrasings matters to users making decisions in real time. Professional communicators in any domain where uncertainty is genuine — medical, financial, scientific, or digital — face the same requirement for epistemic precision that accurate modal use provides.
The Professional Credibility Stakes of Modal Precision
The professional credibility implications of modal choice extend well beyond the narrow question of grammatical correctness. A writer who consistently overuses “will” where “should” or “may” would be more accurate is not simply making a grammar mistake — they are overclaiming certainty they do not have, which creates a credibility problem when the claimed certainty fails to materialise. Conversely, a writer who hedges every claim with “might” or “could” even where the evidence supports considerably stronger language is underperforming professionally, appearing less decisive and confident than their knowledge would justify.
The credibility damage from modal overclaiming is asymmetric and lasting. A professional who says “the project will be complete by Friday” when “should be” or “is expected to be” would be more accurate has made an implicit promise that failure to deliver damages their credibility more than the more tentative formulation would have. The choice of “will” is not merely a language choice — it is a commitment choice, and the grammar reflects the commitment. Understanding this allows writers to make modal choices that accurately represent not just their epistemic state but their professional position on what they are willing to be held accountable for.
Academic and technical writing conventions have developed elaborate systems for managing epistemic modal precision, and these conventions carry information that readers familiar with them decode automatically. The hedging language of academic writing — “results suggest,” “findings may indicate,” “evidence is consistent with” — is not vagueness or timidity but precision: it accurately communicates that the evidence supports a probabilistic inference rather than a certain conclusion, and the absence of these hedges in academic writing is a sign of overclaiming rather than confidence.
Building Modal Precision as a Writing Habit
The Self-Audit Process That Develops Epistemic Accuracy
The development of modal precision requires the same kind of deliberate attention that other writing improvement practices require: identifying the specific patterns in your own writing where modal choice is producing unintended meaning, and replacing those patterns with more accurate alternatives. The general principle — use the modal that accurately reflects your degree of certainty — is simple enough to state. The practice of applying it consistently requires knowing which modal choices you typically make habitually rather than deliberately.
The most common habitual modal error in professional English writing is the use of “will” for future events where the actual certainty is lower than “will” expresses. This error is more prevalent among native speakers than among advanced non-native speakers, because native speakers have internalised “will” as the default future marker and use it automatically rather than selecting it as the highest-certainty option from a range of available alternatives. Non-native speakers who have learned the modal system explicitly often make more accurate modal choices precisely because their choices are deliberate rather than automatic.
The second most common habitual error is the use of “should” as an obligation marker in contexts where it is being read as an epistemic marker, or vice versa. “You should submit your application by Friday” is ambiguous between “you are obligated to submit” (deontic) and “submitting by Friday is likely to produce the best outcome” (epistemic), and the context does not always resolve the ambiguity. Writers who use “should” freely across both functions without attending to whether the deontic or epistemic reading is dominant in the specific sentence they have written create confusion in readers who are trying to determine whether they are being told what to do or what is likely to be true.
The characteristics of modal usage that consistently produce clearer, more credible professional writing are:
- Explicit epistemic grounding — pairing modal choices with the evidence or reasoning that justifies them, so that “results should improve by Q2” is followed by “given the trend established in the last three months,” which both explains the basis for the modal choice and signals to the reader that the word choice is deliberate rather than habitual
- Consistent modal register across a document — maintaining the same epistemic positioning throughout a professional document rather than shifting between confident “will” claims and uncertain “might” hedging without signalling what has changed in the evidence base
- Deontic-epistemic disambiguation — making the intended reading explicit when “should” or “could” are used in contexts where ambiguity is possible, either through context or through explicit rephrasing
The numbered steps for developing modal precision as a deliberate writing practice are as follows:
- Audit the modal verbs in a recent piece of professional writing by listing every instance of will, would, should, may, might, can, could, and must, and for each instance identifying whether the modal is being used epistemically or deontically and whether the certainty level expressed matches your actual certainty about the proposition
- Replace all habitual “will” future markers with the modal that most accurately reflects your actual certainty — “will” if the outcome is as close to certain as language can express, “should” if there are conditions that could produce a different outcome, “may” or “might” if the outcome is genuinely uncertain — and notice whether the document feels less assertive, then consider whether less assertion is more accurate
- Review uses of “should” specifically for the deontic-epistemic ambiguity and rephrase any instance where the intended reading is not immediately clear from context, using “must” or “need to” for clear obligation, “is likely to” for clear epistemic probability, or adding explicit context to disambiguate
- Practice writing the same proposition at different certainty levels by producing five versions of a single claim — using will, should, may, might, and could — and analysing what is different about each version’s communicative meaning and professional positioning
Conclusion: Modals Are Commitments, Not Style Choices
The modal verb a writer chooses is not a stylistic preference between options that all communicate the same thing — it is a precise epistemic or deontic claim with specific implications for what the writer is claiming to know, what they are expressing as possible, and what they are characterising as obligatory. Writers who treat modal choice as a style variable rather than a meaning variable are producing imprecise communication at the grammatical level and unintended commitments at the professional level. The discipline of choosing modals deliberately — of asking, for every use of “will” whether certainty of that level is actually warranted, and for every use of “might” whether the evidence justifies something stronger — produces writing that is more accurate, more credible, and more precisely aligned with what the writer actually knows and intends to communicate. That discipline is the application of grammatical precision to one of the most consequential elements of professional English.
Elsa Lund is a language enthusiast and founder of Grammar Guide, where she shares expert tips on English grammar, writing, and communication. Her clear, practical advice helps readers write with confidence and precision. Follow Elsa for more easy-to-understand grammar tips and writing insights.
