Учительница медленно произносит новое слово, а мы повторяем его вслух.

Учительница means female teacher. Russian often marks the gender of people with different noun forms.

• учитель = male teacher / teacher
• учительница = female teacher

So this sentence tells you the teacher is a woman. In everyday Russian, учительница is a very normal word for a schoolteacher who is female.

Because медленно is an adverb, and it describes how the teacher pronounces the word: slowly.

Compare:

• медленная учительница = a slow female teacher
• учительница медленно произносит = the teacher pronounces slowly

So:

• медленная = adjective, describes a noun
• медленно = adverb, describes a verb

Because the adjective новое has to agree with слово in gender, number, and case.

Here:

• слово = word
• it is neuter
• it is singular
• it is in the nominative case here, because it is the direct object of an inanimate noun phrase in this structure? Actually more simply: after the verb it is the thing being pronounced, and in Russian the adjective still matches the noun form exactly.

So:

• новый = masculine
• новая = feminine
• новое = neuter
• новые = plural

Since слово is neuter singular, you get новое слово.

They are in the present tense, imperfective aspect:

• произносит = she pronounces / is pronouncing
• повторяем = we repeat / are repeating

Russian present-tense forms can describe:

• something happening right now
• something that happens regularly
• a general scene or routine

In this sentence, it can easily mean either:

• The teacher is slowly pronouncing a new word, and we are repeating it aloud
• or a typical classroom action: The teacher slowly pronounces a new word, and we repeat it aloud

The imperfective is used because the actions are presented as a process or ongoing activity, not as a single completed result.

А often connects two parts of a sentence when there is a mild contrast, switch of focus, or “while/and meanwhile” feeling.

Here:

• Учительница ..., а мы ...
• The teacher ..., and/while we ...

So а helps show a shift from what the teacher does to what we do.

Compare roughly:

• и = simple and
• а = and/but/while, with a contrast or change of subject

In this sentence, а sounds very natural because the subject changes from the teacher to we.

Его means it/him here, and it refers to слово (word).

So:

• новое слово = the new word
• повторяем его = we repeat it

Russian often uses a pronoun instead of repeating the noun, just like English does.

Because его is the form used for the direct object here, while оно is the subject form.

Compare:

• Оно новое. = It is new.

  • оно = nominative (subject form)

• Мы повторяем его. = We repeat it.

  • его = accusative (object form)

So even though слово is a neuter noun, the pronoun changes by case:

• оно = subject
• его = object

A useful detail: for masculine and neuter singular pronouns, the accusative/genitive form is often его.

If you kept the noun instead of replacing it with его, you would usually say:

• Мы повторяем новое слово.

Here слово is inanimate neuter singular, and for inanimate nouns, the accusative often looks the same as the nominative. So the form stays слово.

That is why:

• nominative: новое слово
• accusative (inanimate): новое слово

But when you switch to a pronoun, you use его.

Вслух means out loud / aloud.

So:

• повторяем его вслух = we repeat it aloud

It tells you the repetition is spoken, not silent.

This is a common adverb in Russian:

• читать вслух = to read aloud
• сказать вслух = to say out loud
• повторять вслух = to repeat aloud

No, Russian word order is fairly flexible, although some orders sound more natural than others depending on emphasis.

The given sentence is neutral and natural:

• Учительница медленно произносит новое слово, а мы повторяем его вслух.

You could also hear things like:

• Учительница новое слово медленно произносит, а мы его вслух повторяем.
• А мы повторяем его вслух.

But changing the order usually changes the focus or emphasis, not the basic meaning.

For learners, the original order is a very good standard pattern: subject + adverb + verb + object.

Russian does not have articles.

So:

• учительница can mean the teacher or a teacher
• новое слово can mean a new word or the new word

The exact meaning comes from context, not from separate words like a or the.

In this sentence, English would normally translate it with articles because that sounds natural in English:

• The teacher slowly pronounces a new word, and we repeat it aloud.

But Russian simply does not need articles to express that.