Foje mia krajono malaperas, kaj mi devas skribi sur papero per plumo.

Foje means sometimes or at times.

It is placed at the beginning here because it sets the scene for the whole sentence: Sometimes my pencil disappears, and I have to write on paper with a pen.

In Esperanto, adverbs like foje can often move around fairly freely, as long as the meaning stays clear. For example:

• Foje mia krajono malaperas.
• Mia krajono foje malaperas.

Both are understandable, though the first version sounds very natural.

Mia krajono is the subject of the verb malaperas, so it does not take the -n ending.

In Esperanto, the -n ending usually marks the direct object, not the subject.

Here:

• mia krajono = the thing doing the disappearing
• malaperas = disappears

So:

• Mia krajono malaperas = My pencil disappears

If the pencil were a direct object, then you would use -n:

• Mi trovas mian krajonon = I find my pencil

Malaperas comes from:

• aperi = to appear
• malaperi = to disappear

The prefix mal- creates the opposite of a word. It is one of the most common and useful features of Esperanto.

Examples:

• bona = good → malbona = bad
• granda = big → malgranda = small
• fermi = to close → malfermi = to open
• aperi = to appear → malaperi = to disappear

The ending -as shows present tense, so malaperas means disappears / is disappearing.

Esperanto -as is the normal present-tense ending. It can cover several English present-time ideas, depending on context.

So malaperas can correspond to English expressions like:

• disappears
• is disappearing
• goes missing

In this sentence, because of foje, the meaning is habitual: Sometimes my pencil disappears.

Esperanto keeps this simple: present tense for present or habitual action, without needing a lot of different verb forms.

After devas (must / have to), Esperanto uses the infinitive form of the next verb.

So:

• devas = have to / must
• skribi = to write

Together:

• mi devas skribi = I have to write

This is very regular in Esperanto:

• Mi volas manĝi = I want to eat
• Ŝi povas veni = She can come
• Ni devas labori = We must work

There is no special form like English I must write versus I have to write; Esperanto simply uses the modal verb plus infinitive.

These two phrases answer different questions:

• sur papero = on paper → tells you where the writing is
• per plumo = with a pen → tells you by means of what instrument the writing is done

So:

• sur = on
• per = by means of, with
• plumo = pen
• papero = paper

A useful way to think about it:

• sur papero = the surface
• per plumo = the tool

Because writing is normally done on the surface of paper, not in paper.

So Esperanto uses sur (on):

• skribi sur papero = write on paper

If you said en papero, that would mean something more like in paper, which is not the normal idea here.

This matches English closely:

• on paper → sur papero

Per and kun are related but not the same.

• per = by means of / using
• kun = with / together with

In this sentence, the pen is an instrument, so per is the best choice:

• Mi skribas per plumo = I write with a pen

Using kun plumo would sound less natural here, because it focuses more on accompaniment than on instrument.

Compare:

• Mi venis kun mia amiko = I came with my friend
• Mi tranĉas per tranĉilo = I cut with a knife

So for tools and means, per is usually what you want.

Esperanto uses la only when something is definite and specifically identifiable.

Here, the sentence is talking generally:

• writing on paper
• writing with a pen

It does not mean a particular paper or a particular pen already known to the listener. So no la is needed.

Compare:

• Mi skribas sur papero per plumo. = I write on paper with a pen.
• Mi skribas sur la papero per la plumo. = I am writing on the paper with the pen.

The second version would suggest specific, known items.

Yes, krajono means pencil.

It is a straightforward noun:

• krajono = pencil
• krajonoj = pencils
• krajonon = pencil as a direct object

Example:

• Mi havas krajonon. = I have a pencil.
• Miaj krajonoj estas novaj. = My pencils are new.

For a learner, it is also useful to contrast it with:

• plumo = pen

So the sentence creates a clear contrast: the pencil disappears, so the speaker has to use a pen.

In most cases, yes. Kaj is the normal Esperanto word for and.

Here it joins two clauses:

• Foje mia krajono malaperas
• mi devas skribi sur papero per plumo

So:

• ..., kaj mi devas... = ..., and I have to...

It can also join words or phrases:

• pomo kaj pomo = apple and apple
• li kaj ŝi = he and she

It is a very common and simple connector.

Yes. That is a very close literal translation.

Word-for-word, roughly:

• Foje = sometimes
• mia = my
• krajono = pencil
• malaperas = disappears
• kaj = and
• mi = I
• devas = must / have to
• skribi = write
• sur = on
• papero = paper
• per = with / by means of
• plumo = pen

A more natural English translation might be:

• Sometimes my pencil disappears, and I have to write on paper with a pen.

But the literal version is also perfectly understandable.

Plumo is pronounced approximately PLOO-mo, with the stress on the second-to-last syllable: PLU-mo.

Historically, plumo originally meant feather, and from that came the idea of a writing pen, like a quill. In modern Esperanto, it commonly means pen.

So in everyday usage:

• plumo = pen

If context requires, it can also still relate to a feather, but in a sentence about writing, pen is the obvious meaning.