Is it appropriate to use participles for passive voice in Esperanto?

Question

AS mainly shows the present tense of the action, while ANT and AT show the duration or repetition of the action. IS shows that the action occured before the present, while INT and IT show that the actions was completed possibly before another action...

This is what I got about usages of participles on lernu.net. I got to know that the participles and indicative verbs have differences. However, when we implement passive voices, the differences seem to be blurred.

Ŝi skribas la leteron.
"writing" happens at present, or as a habitual action.

La letero estas skribata.
According to the definition on lernu.net, "writing" as a participle, indicates duration or repetition.

So what if I just want to simply express a present action in the passive sentence, not to emphasize that it’s happening now or it’s repetitive?

Answer 1

Writing a letter isn't an instantaneous action. It does take some time, so implying duration shouldn't distort the meaning. Thus

La letero estas skribata (de ŝi).

is the correct passive form for the usual meaning(s) of "Ŝi skribas la leteron.".

See also section Passive — choosing a participle in the lernu grammar chapter you referred to, as well as the corresponding chapter in PMEG 29.2. Pasivo – participelekto.

If it's a habitual action, you can add "ree kaj ree" (again and again) without distorting the meaning:

La letero estas ree kaj ree skribata (de ŝi).

(Implying that she writes the (same?) letter several times, over and over.)

If you can add "plu kaj plu" (more and more / continuously) or "iom post iom" (bit by bit) without distorting the meaning (usually the case for continuous actions), ·at· can also be used. In your example, "iom post iom" does seem a bit akward, but doesn't significantly change the meaning:

La letero estas iom post iom skribata (de ŝi).

As the two grammar resources state, the possibility to form these "control sentences" indicates that skribata is the correct participle here.

Answer 2

The passive voice can be expressed in two ways.

Personless passive

The so called oni-pasivo puts the focus on action, what happens to the object. Cf. man-passive found in many Germanic languages (but not for instance in English).

• Ŝi skribas la leteron → Oni skribas la leteron / La leteron oni skribas.

Here the information who performs the action is lost, but the focus is clearly on the action. This passive is easy to form: just replace the person pronoun with oni. Because of that easiness this is usually the most recommended way to express the passive voice.

Describing passive

The compound passive or esti-pasivo describes the change of state caused by the action.

• Ŝi skriba̲s la leteron → La letero estas skriba̲ta de ŝi.

As Eduardo stated use the same tense in the passive participle as you have in the corresponding active voice verb.

This passive has several points worth noticing:

• the focus is no longer in the action but in a description of the change of the state (this may sound a minor thing but in some contexts it may matter)
• what is conceptually an object (like the letter in your example), is now suddenly a subject (since you just describe the change); this may confuse people with some language backgrounds
• you can form this form only from transitive verbs, i.e. you cannot say *estas kurata* (in comparison oni kuras is fine)
• in this kind of passive sentence de always marks the agent which causes problems should you need to use de for some other purpose (and de is the most overloaded preposition in Esperanto, see PIV)

Answer 3

So what if I just want to simply express a present action in the passive sentence, just like the active one?

Short answer: You would then stick to the a/i/o ending in the active form:

mi farbas la domon -> la domo estas farbata

The action is in progress.

mi farbis la domon -> la domo estas farbita

The action is completed.

mi farbos la domon -> la domo estas farbota

The action will start in the future.

Note that, if you don't want to lose information, you have to add the active agent, in these cases: de mi.