Мы так и не выбрали кличку для щенка, хотя он уже живёт у нас неделю.

Так и не is a very common Russian pattern meaning something like still didn’t, never did after all, or ended up not doing something.

So Мы так и не выбрали... does not just mean We didn’t choose... It suggests there was an expectation that we would choose a name, but that never happened.

A good rough sense is:

• Мы не выбрали кличку = We didn’t choose a name.
• Мы так и не выбрали кличку = We still haven’t chosen a name / We never did choose a name.

It often carries a mild feeling of frustration, delay, or unmet expectation.

This is about aspect.

• выбрать = perfective, meaning to choose / to make the choice
• выбирать = imperfective, meaning to be choosing / to choose repeatedly / to spend time choosing

In так и не + perfective, Russian usually focuses on the fact that the expected result never happened.

So:

• так и не выбрали = we never actually got to the result of choosing
• так и не выбирали would sound different and usually means we never even tried choosing or never engaged in the process, depending on context

Here the point is not the process, but the missing result: no name was chosen.

Because кличку is the accusative singular form of кличка.

The verb выбрать takes a direct object, and direct objects are often in the accusative case.

So:

• nominative: кличка
• accusative: кличку

Compare:

• Кличка хорошая. = The name is good.
• Мы выбрали кличку. = We chose a name.

Кличка is typically used for an animal’s name.

Имя is used for a person’s name, though sometimes people also use имя for a pet in casual speech.

So in this sentence, кличка is the most standard word because we are talking about a puppy.

A rough distinction:

• имя = name
• кличка = pet name / animal name

Also, кличка can sometimes mean nickname in a negative or rough sense when talking about people, so learners should be careful with it.

Because the preposition для requires the genitive case.

• щенок = puppy
• genitive singular: щенка

So:

• для щенка = for the puppy

This is simply the normal case pattern after для.

Russian often uses the present tense where English uses the present perfect continuous.

So:

• он уже живёт у нас неделю literally: he already lives with us a week naturally in English: he has already been living with us for a week

Russian does not have a separate tense exactly like English has been living, so the present tense often covers that meaning when the action started in the past and is still continuing now.

Because Russian often uses the accusative case to express duration.

Here неделю means for a week.

Compare:

• ждать час = to wait for an hour
• работать весь день = to work all day
• жить у нас неделю = to live with us for a week

So неделю is accusative singular, used to show how long the situation has lasted.

Here у нас means at our place, in our home, or with us.

Literally, у often has the sense of by / at someone. In many everyday situations:

• Я был у друга. = I was at my friend’s place.
• Он живёт у нас. = He lives with us / He’s staying at our place.

So in this sentence, у нас is not just physical location; it also implies being part of our household.

Because хотя introduces a subordinate clause meaning although / though.

Russian normally separates this kind of clause with a comma:

• Мы так и не выбрали кличку для щенка, хотя он уже живёт у нас неделю.

This is very similar to English punctuation with although, though Russian is generally more consistent about using commas before subordinate clauses.

Yes, it often could be omitted if the context is clear.

Russian often drops subject pronouns because the verb form already gives useful information. Выбрали already shows we or they, depending on context, and the surrounding situation often makes it clear.

So you might hear:

• Так и не выбрали кличку для щенка...

But including мы is also perfectly natural. It can make the sentence clearer or slightly more explicit.

Some parts are flexible, but some are much less flexible.

The phrase так и не is basically a set pattern and normally stays together before the verb:

• Мы так и не выбрали... ✅

A version like Мы не так и выбрали... is wrong.

Other parts are more movable:

• Хотя он уже живёт у нас неделю
• Хотя он у нас уже неделю живёт
• Хотя он уже неделю живёт у нас

These can all be possible, but they shift emphasis a little. The original version is very natural and neutral.

Уже means already, and it emphasizes that a surprisingly long or important amount of time has passed.

So:

• он живёт у нас неделю = he has been living with us for a week
• он уже живёт у нас неделю = he’s already been living with us for a week

That already helps support the contrast with так и не выбрали: the puppy has been with us for a whole week, and yet we still have not chosen a name.

Yes. In everyday Russian writing, ё is often replaced by е.

So both of these may appear:

• живёт
• живет

They are understood as the same word here. Learners are often shown ё because it helps with pronunciation and stress, but native texts frequently omit the dots.

So if you see он уже живет у нас неделю, it means the same thing.