La folioj velkas sen akvo.

La is the definite article, equivalent to the in English.

So la folioj means the leaves.

Esperanto has only one article, la. It does not change for singular/plural, gender, or case. In this sentence, it points to a specific set of leaves, or leaves being talked about in a general but definite way.

The ending -j marks the plural in Esperanto.

• folio = a leaf
• folioj = leaves

So:

• la folio = the leaf
• la folioj = the leaves

This is one of the most regular parts of Esperanto grammar: nouns end in -o, and plurals add -j.

Because Esperanto nouns must end in -o in their basic form.

The structure is:

• foli- = the root related to leaf
• -o = noun ending
• -j = plural ending

So:

• folio = leaf
• folioj = leaves

In Esperanto, word endings tell you the part of speech very clearly, so -o is important.

Velkas means wilt, are wilting, or wither, depending on context.

It is made from:

• velk- = the root meaning wilt / wither
• -as = present tense verb ending

So velkas means wilts / are wilting / wilt in the present.

Esperanto verbs are very regular:

• -as = present
• -is = past
• -os = future
• -us = conditional
• -u = command / wish
• -i = infinitive

So velkas is simply the present-tense form.

Because Esperanto usually does not need an extra helping verb like English does.

In English, we often say the leaves are wilting. In Esperanto, the tense is already built into the verb ending:

• velkas already shows present time

So La folioj velkas is a complete sentence by itself.

This is very normal in Esperanto. The verb ending does a lot of work.

Sen means without.

So sen akvo means without water.

This is a prepositional phrase:

• sen = without
• akvo = water

Together they explain the condition under which the leaves wilt.

Because after sen, you normally use the ordinary noun form, not the accusative.

• akvo = water
• akvon = water as a direct object

But here akvo is not the direct object of a verb. It is the object of the preposition sen. In Esperanto, prepositions normally take the basic form, not -n.

So:

• sen akvo = correct
• sen akvon = not correct here

Because the sentence is talking about water in a general sense, not a specific, already identified water.

• sen akvo = without water
• sen la akvo = without the water

In English we also often omit the with substances when speaking generally:

• without water
• not necessarily without the water

So akvo without la is the natural choice here.

The word order is fairly flexible.

La folioj velkas sen akvo is natural and straightforward, but you could also say:

• Sen akvo la folioj velkas.

That puts more emphasis on without water.

Because Esperanto marks grammar with endings, word order is often freer than in English. The original order is just the most neutral one.

Folioj is pronounced roughly fo-LEE-oy.

A more careful breakdown is:

• fo
• li
• oj

Important points:

• j in Esperanto sounds like English y
• oj sounds roughly like oy in boy
• the stress falls on the second-to-last syllable: fo-LI-oj

So the stress is on LI.

Velkas is pronounced roughly VEL-kas.

Breakdown:

• vel
• kas

The stress is on the second-to-last syllable, so here it falls on VEL.

That same stress rule works for almost all Esperanto words: stress the next-to-last syllable.

Possibly, depending on context, but velkas most directly suggests wilting or withering.

For leaves, wilt is usually the best natural translation. English might choose different verbs depending on the situation:

• The leaves wilt without water.
• The leaves are wilting without water.
• The leaves wither without water.

So the exact English wording can vary, but the Esperanto grammar stays the same.

It breaks down like this:

• La folioj = the subject, the leaves
• velkas = the verb, wilt / are wilting
• sen akvo = a prepositional phrase, without water

So the pattern is:

subject + verb + prepositional phrase

That makes this a very typical simple Esperanto sentence.