Мы практически закончили.

Because the subject is мы (we), which is plural.

In the Russian past tense, verbs agree with the subject in number, and in the singular they also agree in gender:

• я закончил — I finished (masculine speaker)
• я закончила — I finished (feminine speaker)
• оно закончило — it finished
• мы закончили — we finished

So -ли is the normal plural past-tense ending.

The infinitive is закончить, meaning to finish.

So:

• закончить — to finish
• мы закончили — we finished / we have finished

This is the perfective verb, which matters a lot in Russian.

Because закончили is perfective, and here the speaker is talking about reaching the end of something, or being very close to that completed result.

Compare:

• Мы practically закончили. — We’ve practically finished / We’re almost done.
• Мы заканчивали. — We were finishing / We used to finish / We finished repeatedly in some context.

The imperfective заканчивать / заканчивали does not focus on the completed result. In this sentence, the idea is clearly about being near completion, so perfective is the natural choice.

Here практически means almost, nearly, or for all practical purposes.

So the sentence means something like:

• We’ve practically finished
• We’re almost done
• We’ve nearly finished

In other contexts, практически can also mean practically in the sense of in practice or essentially, but in this sentence it is modifying the idea of finishing and means almost.

In this sentence, практически and почти are very close in meaning.

• Мы практически закончили.
• Мы почти закончили.

Both can mean We’re almost done.

However, почти is often the more direct, everyday word for almost.
Практически can sound a little more formal, bookish, or like for all practical purposes.

So if you are a learner, почти закончили is very useful and common, but практически закончили is also perfectly natural.

Russian often leaves out the object if it is already understood from context.

So Мы практически закончили could mean:

• we’ve practically finished the work
• we’ve practically finished the project
• we’ve practically finished it

The listener is expected to know what is being talked about. English does this too: We’re almost done often leaves the object unstated.

Yes, very often.

Russian does not always need the subject pronoun if it is clear from context. So you could also say:

• Практически закончили.

That would still mean We’ve practically finished if the context makes we obvious.

Including мы can make the subject clearer or slightly more emphatic.

Because Russian and English package this idea differently.

Russian uses the past-tense verb закончили, but the overall meaning can correspond to English:

• We’ve practically finished
• We’re almost done

Russian does not need an auxiliary verb like have. A simple past-tense form often covers what English expresses with either the simple past or the present perfect, depending on context.

No, Russian word order is flexible, but different orders change the emphasis.

The neutral order here is:

• Мы practically закончили.

Other possibilities:

• Практически закончили. — natural if the subject is understood
• Мы закончили практически... — possible, but it often sounds like something should follow
• Практически мы закончили. — gives special emphasis or contrast to мы

So the original sentence is a normal, neutral way to say it.

The stress is:

• мы практи́чески зако́нчили

A rough pronunciation guide:

• мы — mɨ
• практи́чески — stress on -ти́-
• зако́нчили — stress on -ко́н-

If you want a simple English-style approximation, it is something like:

• muh prak-TEE-chee-skee za-KON-chee-lee

That approximation is not exact, but it helps you place the stress correctly.

They can both mean finished, but закончить / закончили is the safer and more neutral choice for learners.

• Мы закончили. — We finished.
• Мы кончили. — can also mean We finished, but it may sound more colloquial and can have unwanted meanings in some contexts.

So in most neutral situations, especially as a learner, prefer закончить.

It can overlap with that idea, but in normal use Мы practically закончили usually means the work is nearly complete now, not that you failed to finish in the past.

In English, We almost finished can sometimes suggest but didn’t quite finish as a completed past event. Russian Мы practically закончили more naturally expresses the current state of being almost done.

So in most contexts, the best feel is:

• We’ve practically finished
• We’re almost done