На завтрак дочка выбрала йогурт и ананас.

На завтрак means for breakfast or as breakfast.

Russian often uses на + accusative to talk about food chosen, prepared, or eaten for a meal:

• на завтрак = for breakfast
• на обед = for lunch
• на ужин = for dinner

Putting На завтрак first gives the time/occasion first, something like:

• As for breakfast, the daughter chose yogurt and pineapple.

It is very natural in Russian to begin a sentence with this kind of context.

It is in the accusative case after the preposition на.

The pattern is:

• на завтрак
• на обед
• на ужин

For masculine inanimate nouns like завтрак, the accusative singular looks the same as the nominative singular, so the form stays завтрак.

Both mean daughter, but they are a little different in tone:

• дочь = the basic, neutral word
• дочка = a more affectionate, everyday, warmer version

So дочка can sound a bit more personal or natural in family-style speech.

Compare:

• Дочь выбрала... = more neutral
• Дочка выбрала... = warmer, more conversational

Выбрала is the past tense, feminine singular form of выбрать = to choose/select.

Russian past tense agrees with the subject in gender and number:

• выбрал = he chose
• выбрала = she chose
• выбрало = it chose
• выбрали = they chose

Since дочка is feminine singular, the verb must be выбрала.

This is about aspect.

• выбрать / выбрала = perfective: completed action, a finished choice
• выбирать / выбирала = imperfective: process, repeated action, or focusing on the act of choosing

In this sentence, the daughter made a completed choice, so выбрала is the natural form.

Very roughly:

• дочка выбрала йогурт и ананас = she chose yogurt and pineapple
• дочка выбирала йогурт и ананас = she was choosing / used to choose / was in the process of choosing yogurt and pineapple

They are in the accusative singular, because they are the direct objects of выбрала.

Both йогурт and ананас are masculine inanimate nouns. In Russian, masculine inanimate nouns usually have the same form in:

• nominative singular
• accusative singular

So:

• йогурт stays йогурт
• ананас stays ананас

That is why you do not see any extra endings here.

Russian does not have articles like English a/an and the.

So дочка, йогурт, and ананас can mean:

• the daughter
• a daughter
• yogurt / a yogurt / the yogurt
• a pineapple / the pineapple

The exact meaning depends on context. In this sentence, English would usually translate it naturally as something like The daughter chose yogurt and pineapple for breakfast, but Russian does not need articles to express that.

Yes. Russian word order is fairly flexible.

This sentence is:

• На завтрак дочка выбрала йогурт и ананас.

But you could also say:

• Дочка выбрала на завтрак йогурт и ананас.
• Йогурт и ананас дочка выбрала на завтрак.

The basic meaning stays the same, but the emphasis changes.

For example:

• На завтрак... puts breakfast first as the setting
• Дочка... puts focus first on the daughter
• Йогурт и ананас... highlights what she chose

So the original sentence is natural and sounds like it is first telling you for breakfast and then what happened.

Yes. Ананас is the standard Russian word for pineapple.

Its singular and plural are:

• ананас = pineapple
• ананасы = pineapples

So in this sentence, ананас is simply pineapple in the singular.

The stress is:

• На зАвтрак дОчка вЫбрала йОгурт и ананАс.

A rough pronunciation guide:

• На = nah
• завтрак = ZAV-trak
• дочка = DOCH-ka
• выбрала = VY-bra-la
• йогурт = YO-gurt
• и = ee
• ананас = a-na-NAS

A few useful notes:

• дочк- has the чк sound, like ch
  • k
• unstressed о is often reduced in actual pronunciation
• ы in выбрала is a Russian vowel that does not exist exactly in English

By itself, йогурт и ананас most naturally means yogurt and pineapple as two coordinated items.

If Russian wanted to make pineapple yogurt clearer, it would usually say something more specific, for example:

• ананасовый йогурт = pineapple yogurt
• йогурт с ананасом = yogurt with pineapple

So in your sentence, the most straightforward reading is that she chose yogurt and pineapple.