La ŝoforo devas halti ĉe la ruĝa semaforo.

Esperanto word endings tell you a lot:

• ŝofor-o: -o marks a noun, so ŝoforo is a noun.
• dev-as: -as marks a present-tense verb, so devas means something like must / has to in the present.
• halt-i: -i marks the infinitive, so halti means to stop.
• ĉe: this is a preposition.
• ruĝ-a: -a marks an adjective, so ruĝa means red as a describing word.
• semafor-o: again -o, so it is a noun.

This regular system is one of Esperanto’s biggest advantages.

Because both nouns are definite:

• la ŝoforo = the driver
• la ruĝa semaforo = the red traffic light

Esperanto has only one definite article: la. It does not change for gender, number, or case.

Also, Esperanto has no separate word for a/an. So:

• ŝoforo = a driver or just driver
• la ŝoforo = the driver

Devas comes from devi, which means to have to, to must, or more naturally in English, must / have to / be required to.

So devas halti means must stop or has to stop.

A useful thing to notice: Esperanto verbs do not change according to person.

• mi devas = I must
• vi devas = you must
• li devas = he must
• la ŝoforo devas = the driver must

The form devas stays the same.

After devas, the next verb stays in the infinitive.

So:

• devas halti = must stop
• not devas haltas

This works much like English:

• The driver must stop
• not The driver must stops

In Esperanto, the tense is carried by the first verb:

• devas halti = must stop
• devis halti = had to stop
• devos halti = will have to stop

Because there is no direct object here.

• La ŝoforo is the subject, so it does not take -n.
• ĉe la ruĝa semaforo is a prepositional phrase, and after a normal preposition like ĉe, you usually do not use -n.

The -n ending is mainly used for:

1. direct objects
2. sometimes direction or motion toward something

Here, the sentence is about stopping at a location, not moving toward it as the grammar focus, so no -n is needed.

Here ĉe means something like at, by, or near.

So ĉe la ruĝa semaforo means at the red traffic light.

Why not the others?

• en = in / inside
  • That would sound wrong here, because the driver is not inside the traffic light.
• al = to / toward
  • That would emphasize movement toward it, not the location where the stopping happens.

So ĉe is the natural choice for stopping at a traffic light.

Because ruĝa is an adjective, and adjectives in Esperanto end in -a.

It describes semaforo:

• ruĝa semaforo = red traffic light

Adjectives also agree with the noun in number and case. For example:

• ruĝa semaforo = red traffic light
• ruĝaj semaforoj = red traffic lights
• ruĝan semaforon = red traffic light as a direct object
• ruĝajn semaforojn = red traffic lights as direct objects

In your sentence, it is singular and not accusative, so ruĝa is the correct form.

Halti means to stop, to come to a stop, or to stop moving oneself. It is intransitive.

So:

• La ŝoforo haltas = The driver stops.

If you want to say to stop something, Esperanto often uses haltigi, which is causative:

• La ŝoforo haltigas la aŭton = The driver stops the car.

So in your sentence, devas halti means the driver must come to a stop.

Yes. Semaforo is the standard Esperanto word for a traffic light or traffic signal.

So la ruĝa semaforo is a normal way to say the red traffic light or the traffic light when it is red.

You may also see ruĝa lumo for red light, but semaforo specifically names the traffic signal itself.

Normally, no. In context, it means the traffic signal is showing red, not that the whole object is painted red.

This is similar to English, where at the red light usually means at the traffic light when the red signal is on.

So learners should understand this as the usual road-traffic meaning, not a description of the object’s permanent color.

These special letters are very regular:

• ŝ sounds like sh in ship
  • ŝoforo
• ĝ sounds like j in judge
  • ruĝa
• ĉ sounds like ch in church
  • ĉe

Approximate pronunciation of the whole sentence:

la sho-FO-ro DE-vas HAL-ti cheh la RU-jah se-ma-FO-ro

Also remember: Esperanto stress is almost always on the next-to-last syllable.

• ŝoFOro
• DEvas
• HALti
• RUĝa
• semaFOro

Yes. Esperanto word order is fairly flexible.

The neutral order here is:

• La ŝoforo devas halti ĉe la ruĝa semaforo.

But you could also say:

• Ĉe la ruĝa semaforo la ŝoforo devas halti.

That puts more focus on the location first: At the red traffic light, the driver must stop.

Even so, the original version is the most straightforward and neutral for beginners.