Ĉe tiu angulo vi devas iri maldekstre.

Ĉe is a preposition that often means at, by, or near. In this sentence, Ĉe tiu angulo means something like At that corner or At that point/corner.

English often uses several different prepositions depending on context, but Esperanto ĉe is fairly broad. Here it tells you the place where the action becomes relevant: when you get to that corner, you should turn left.

Because ĉe is a preposition, and in normal Esperanto, prepositions are followed by the nominative, not the accusative.

So:

• tiu angulo = that corner
• ĉe tiu angulo = at that corner

You would use -n on a noun mainly for the direct object, or sometimes for direction in certain expressions. But after ĉe, you normally do not add -n.

Literally, angulo means angle, but in everyday use it can also mean corner, especially in directions and street contexts.

So in this sentence, tiu angulo is naturally understood as that corner. A learner might think only of a geometric angle, but Esperanto uses angulo in the practical sense too.

In standard Esperanto, subject pronouns are normally stated, so vi is included to mean you.

• vi devas iri maldekstre = you must go left

Unlike some languages, Esperanto usually does not drop the subject pronoun in ordinary sentences. So vi is the normal and expected form here.

Devas comes from the verb devi, meaning to have to, must, or to be obliged to.

The ending -as shows the present tense, so:

• mi devas = I must / I have to
• vi devas = you must / you have to
• li devas = he must

In Esperanto, all present-tense verbs end in -as, no matter who the subject is. So there is no change like English I go / he goes.

This is very normal in Esperanto. Devi is followed by an infinitive, just like must or have to in English is followed by another verb.

• devi = to have to
• iri = to go

So:

• vi devas iri = you have to go

The second verb stays in the infinitive form -i.

Esperanto often expresses direction in a very straightforward way. Iri maldekstre literally means go left or go to the left, and in directional instructions it can naturally mean turn left.

Depending on context, Esperanto speakers might also say things like:

• turni maldekstren = turn left
• iri maldekstren = go left

But iri maldekstre is perfectly understandable in giving directions, especially if the meaning is already clear from context.

This is a very common question.

• maldekstre = on the left / leftward / to the left as an adverb of position or general direction
• maldekstren = specifically shows motion toward the left with the accusative -n

So both can appear in direction-related sentences, but maldekstren more clearly emphasizes movement in that direction.

Examples:

• Li staras maldekstre. = He is standing on the left.
• Li iras maldekstren. = He is going left.

In actual usage, maldekstre is also commonly used in instructions like this one, and it is easy to understand.

Esperanto builds many words from smaller meaningful parts.

maldekstre = mal- + dekstr- + -e

• dekstra = right (the right-hand side)
• mal- = the opposite
• maldekstra = left
• -e = adverb ending

So maldekstre means to the left / leftward / on the left.

This is a very typical Esperanto pattern. The prefix mal- makes the opposite of a word:

• bona = good → malbona = bad
• granda = big → malgranda = small
• dekstra = right → maldekstra = left

Because here it is an adverb, not an adjective.

• maldekstra = left as an adjective, used with a noun
  
  • la maldekstra mano = the left hand
• maldekstre = left / on the left / to the left as an adverb
  
  • iru maldekstre = go left

Since it describes how / in what direction you go, Esperanto uses the adverb ending -e.

Esperanto word order is fairly flexible, though some orders sound more natural than others.

This sentence:

• Ĉe tiu angulo vi devas iri maldekstre.

could also be expressed in ways like:

• Vi devas iri maldekstre ĉe tiu angulo.
• Maldekstre vi devas iri ĉe tiu angulo. (less neutral, more emphasis)

The original sentence starts with Ĉe tiu angulo to set the scene first: At that corner... That is very natural in giving directions.

Ĉ is pronounced like ch in church.

So:

• ĉe sounds roughly like cheh

A few other useful Esperanto letters for comparison:

• c = ts
• ĉ = ch
• j = English y
• ŝ = sh
• ĝ = soft j as in judge

Usually devas is fairly strong: must, have to, need to.

In a directions context, though, it often means this is what you should do if you want to follow the route correctly. So it may sound less like an order and more like necessary guidance.

If someone wanted to sound softer, they might use:

• vi povas iri maldekstre = you can go left
• vi iru maldekstre = go left / please go left (imperative)
• vi devus iri maldekstre = you should go left

So devas suggests necessity more strongly than simple advice.

In theory, angulo can mean angle, but in this sentence the context of movement and direction makes corner the natural reading.

Because the sentence is about where to go, a learner should understand Ĉe tiu angulo as At that corner rather than a geometric angle. Context is doing a lot of work here, just as it often does in English.