La valideco de la pasporto daŭras dek jarojn.

Valideco means validity, the abstract quality or period of being valid. The sentence is talking about the validity of the passport, not directly describing the passport with an adjective.

• valida = valid
• valideco = validity

So:

• La pasporto estas valida. = The passport is valid.
• La valideco de la pasporto... = The validity of the passport...

The ending -ec- is a very common Esperanto suffix that turns a quality into an abstract noun.

The suffix -ec- means quality, state, or abstract property.

So:

• valida = valid
• valideco = validity

Some similar examples:

• bela = beautiful

• beleco = beauty

• grava = important
• graveco = importance

This is one of the most useful word-building patterns in Esperanto.

de often means of and is used to show possession or relationship.

So la valideco de la pasporto literally means:

the validity of the passport

This is the normal Esperanto way to express this idea. English often uses noun + noun combinations, but Esperanto usually prefers de in cases like this.

Compare:

• la pordo de la domo = the door of the house
• la nomo de la urbo = the name of the city
• la valideco de la pasporto = the validity of the passport

Both nouns are definite here.

• la valideco = the specific validity being discussed
• la pasporto = the specific passport being discussed

Esperanto uses la much like English the, but often more straightforwardly. If both nouns are definite in meaning, both can take la.

So this sentence is not talking about passports in general, but about the validity of the passport.

daŭri means to last, to continue, or to endure for some time.

Here, daŭras means lasts:

• La valideco de la pasporto daŭras dek jarojn.
• The validity of the passport lasts ten years.

This is a very natural verb when talking about time spans:

• La kunveno daŭris du horojn. = The meeting lasted two hours.
• La ferio daŭros unu semajnon. = The vacation will last one week.

The -n on jarojn is the accusative of duration. In Esperanto, a period of time can take -n without a preposition to show how long something lasts.

So:

• daŭras dek jarojn = lasts ten years
• laboris tri horojn = worked for three hours
• atendis la tutan tagon = waited the whole day

This -n does not mean that years is a normal direct object in the same way as in many other sentences. It is specifically a time-expression use of the accusative.

Yes, often you can express duration either way:

• daŭras dek jarojn
• daŭras dum dek jaroj

Both can be understood, but dek jarojn is usually the more compact and more idiomatic Esperanto way to express duration.

So the sentence with -n sounds very normal.

It is correct, and it sounds somewhat formal or administrative, which fits the topic.

But Esperanto also commonly says the same idea in other ways, for example:

• La pasporto validas dek jarojn.
• La pasporto estas valida dum dek jaroj.

These are often more direct in everyday language.

So the original sentence is good, especially in official or explanatory contexts, but it is not the only natural option.

Yes. Esperanto often allows a root to function in more than one grammatical form.

So from the root valid- you can get:

• valida = valid
• valideco = validity
• validi = to be valid

That is why this is possible:

• La pasporto validas dek jarojn.

This literally means The passport is valid for ten years.

Because dek means ten, and that requires a plural noun:

• unu jaro = one year
• du jaroj = two years
• dek jaroj = ten years

Since the sentence uses the duration accusative, the full form becomes dek jarojn.

Yes. Esperanto word order is fairly flexible, because endings show grammatical roles clearly.

For example, you could also say:

• Dek jarojn daŭras la valideco de la pasporto.

That puts emphasis on ten years.

But the original order is the most neutral and easiest for learners:

• La valideco de la pasporto daŭras dek jarojn.

Yes. Pasporto is the standard Esperanto word for passport.

It is a regular noun, so:

• singular: pasporto
• plural: pasportoj
• accusative singular: pasporton
• accusative plural: pasportojn

In your sentence, it stays as pasporto because it is inside the de phrase: de la pasporto.

Because pasporto is not the direct object here.

It is part of the prepositional phrase de la pasporto. After a preposition like de, nouns normally do not take -n.

So:

• la valideco de la pasporto = the validity of the passport

The -n instead appears on jarojn, because that is a duration expression.

As written, it most naturally refers to a specific passport, or to a passport in a specific context, because of la pasporto.

If you wanted a more general statement about passports as a category, you would usually phrase it differently, for example:

• La valideco de pasportoj daŭras dek jarojn. = The validity of passports lasts ten years.
• Pasportoj validas dek jarojn. = Passports are valid for ten years.

So the original sentence sounds like the passport’s validity lasts ten years rather than a broad general rule about all passports everywhere.