B2 — upper-intermediateModality

Epistemic modality

Lesson opening

This is the first part of the lesson. The rest, the exercises and the reviews are in the app.

Epistemic modality: mora da, biće da and the scale of certainty

Modality is everything a speaker adds to a bare fact: “must”, “may”, “probably”. So far in this course it has been about deeds: who is obliged, who is allowed, who ought to. The lesson “Core modal verbs” gave you moram, mogu, smem, and “treba & valja” the whole family of “need to”. That is the modality of duty and permission, which linguists call deontic: talk about what the world should become.

Today we turn to the other half. It is about what we know of the world: how sure the speaker is that what they say is true. “He’s at work” is a fact. “He must be at work”, “He’s probably at work”, “Maybe he’s at work” are three degrees of certainty about one and the same thing. The lesson “Modal & sentence adverbs” gave you single words for this (sigurno, verovatno, možda). Now come the phrases: mora da, biće da, može biti da, rekao bih da, ne mora da znači, the machinery Serbian uses to build inference, supposition and doubt.

One verb, two meanings: moram and mora da

The difference is easiest to see with morati. English must already does double duty: “You must go” is an obligation, “He must be tired” is a conclusion. Serbian keeps the two apart by grammar. For a duty, morati is an ordinary verb that changes with the person (moram, moraš, mora…). For a guess, it freezes as mora, and a whole sentence with its own subject follows da.

Examples

Duty	Guess (conclusion)
Moram da idem. I have to go.	Mora da je otišao. He must have left.
Moraš da učiš. You have to study.	Mora da si umoran. You must be tired.
Marko mora da bude na poslu u osam. Marko has to be at work at eight.	Mora da je Marko na poslu. Marko must be at work.

There are two reliable signs of a guess. The first is a mismatch of person. In Mora da si umoran the verb mora is 3rd person, while si (“you are”) is 2nd person. A duty never does that: it changes its form with the person (moraš, moram). When you see mora next to si, sam or su, you are looking at a conclusion.

The second sign is je, su or sam straight after da, the short forms of biti “to be”. A duty is about doing something: mora da bude (there), mora da radi. But Mora da je Marko na poslu, with a ready-made je, can no longer be a duty: you can oblige someone to do something, not to what already is or has already happened. So when you hear mora da je, mora da su, mora da sam, translate with confidence: “must be”, “must have”.

When there is no such sign, and mora da is followed by an ordinary verb in the same 3rd person, the situation decides. Mora da radi can mean “he has to work” or “he must be working”:

Sutra mora da radi ceo dan, pa ne može da dođe. Tomorrow he has to work all day, so he can’t come.

U kancelariji još gori svetlo, mora da radi. The light’s still on in the office, so he must be working.

The first is about what he has to do; the second explains what you can see, and that is a guess.

Deeper history

Why “must” turns into “must be” in language after language

Serbian mora da follows one of the most well-trodden paths in the history of languages. In many languages a verb of necessity sooner or later acquires a second, “guessing” meaning: English must (“he must be tired”), German muss (er muss müde sein), French devoir (il doit être fatigué), Spanish deber de (debe de estar cansado). The American linguists Joan Bybee, Revere Perkins and William Pagliuca, in The Evolution of Grammar (1994), followed this route across a sample of the world’s languages and described it as one of the regular directions of grammaticalisation, the process by which words turn into grammar.

The logic of the shift is elegant. Obligation says: “the world has no other way out.” Inference says: “the facts have no other explanation.” Carry “no other way out” over from actions to truth, and obligation becomes a conclusion. The Serbian adverb valjda “I suppose, presumably” travelled the same road (from valja da “it is fitting that”), and, as we shall see in a moment, so did biće da.

mora da: a conclusion you cannot escape

mora da is the strongest guess the language has, close to certainty: English “must”, “surely”, “no doubt”. It says: I did not see it myself, but the facts leave no other explanation. So it will not do for a polite “well, maybe”: with mora da you claim to know the answer; you just got it by reasoning rather than with your own eyes.

The last example shows that you can draw conclusions about yourself too: mora da sam… “I must have…”. Even here the form mora does not change; sam takes care of the person. The subject may also stand in front, and mora still does not change: Ti mora da si umoran. “You must be tired.”

The phrase has a slightly more bookish twin, mora biti da, with the infinitive biti “to be” inserted after mora: Mora biti da je zaboravio. He must have forgotten. The meaning is the same, the sound weightier; it suits written language. In conversation the short mora da wins.

Watch out

Typical mistakes of English speakers, 1: translating “must be” and “must have” word for word. “He must be at home” comes out as “On mora biti kod kuće” or “On mora da bude kod kuće”; “He must have forgotten” as “On mora imati zaboravio”. Why it is wrong: morati with a subject and a following verb reads first as a duty: “he is obliged to be at home”, an order rather than a guess; only context could turn it into a guess. And the English “have” of “must have” has no place here at all: Serbian puts the past into the part after da, not onto mora. Only frozen mora + da with a whole sentence after it gives the guess without ambiguity. The correct form: Mora da je kod kuće. He must be at home. Mora da je zaboravio. He must have forgotten. The person is shown by je after da, and mora belongs to nobody.

Placing the guess in time

The phrase itself has no tense: a conclusion is always drawn now, at the moment of speaking. The time of the event is set by the verb after da, and all your tenses are at work there.

Cheat sheet

The cheat sheet — everything essential from the lesson on one page. In the app it opens at any time.

Epistemic modality: guess, conclusion, doubt

Duty: moram da idem. A guess: how sure the speaker is that it is true. Guessing phrases freeze in the 3rd person and take da + a sentence; person and tense sit after da.

One verb, two meanings

Examples

Duty	Guess
Moraš da učiš. You have to study.	Mora da si umoran. You must be tired.
Marko mora da bude na poslu. Marko has to be at work.	Mora da je Marko na poslu. Marko must be at work.

Signs of a guess: 1) persons don’t match (mora 3rd + si 2nd); 2) je / su / sam right after da. Otherwise the situation decides: Sutra mora da radi ceo dan (duty); U kancelariji još gori svetlo, mora da radi (guess). The subject may go first: Ti mora da si umoran.

Time goes after da

mora never moves in time: Morao je da spava is “he had to sleep”, a duty, not a guess.

Phrases by strength

Future as a guess: Biće mu oko četrdeset godina. He’ll be about forty. At the door: To će biti Marko. trebalo bi da = advice (Trebalo bi da odeš kod lekara) or an expectation, like English “should” (Trebalo bi da je već kod kuće); Trebalo je da stigne u pet, ali kasni = a plan that failed, not a guess.

Negation on two floors

ne mora is never “must not”.

A guess as a question

da + negative verb: Da nije bolestan? He isn’t ill, is he? Also Da se nije izgubio? With “!”, Da nisi…! = “Don’t you dare!”

now	Mora da spava. He must be asleep.
then	Mora da je spavao. He must have been asleep.
later	Mora da će zakasniti. He’s bound to be late.

mora da, bookish mora biti da	Mora da je kod kuće. He must be at home.
biće da, negative neće biti da	Biće da je zaboravio. He’s probably forgotten.
rekao bih da (woman: rekla bih da), reklo bi se da	Rekao bih da ima trideset godina. I’d say he’s about thirty.
može biti da, moguće je da	Može biti da je pogrešio. Maybe he made a mistake.
mogao bi da bude, moglo bi da bude	Moglo bi da bude problema. There could be problems.
nije isključeno da, postoji šansa da	Nije isključeno da otkažu let. They may well cancel the flight.
teško da, sumnjam da, ne bih rekao da	Teško da će doći. He’s hardly likely to come.
nema šanse da, ne može biti da	Nema šanse da je on to uradio. No way he did that.

Mora da nije čuo.	event negated: he must not have heard
Ne mora da je čuo.	conclusion negated: not necessarily
Ne mora da znači.	“not necessarily, that proves nothing”