Летом мы собираем черешню, а осенью бабушка печёт сладкую тыкву.

Russian often uses certain nouns in special case forms to express time without any preposition.

• летом = in summer
• осенью = in autumn

This is very common with seasons, times of day, and some other time expressions:

• утром = in the morning
• днём = in the daytime
• вечером = in the evening
• зимой = in winter

So Летом мы собираем черешню literally looks like Summer-INS we gather cherries, but the natural meaning is In summer we pick sweet cherries.

They are both in the instrumental case, used here in a time expression.

Dictionary forms:

• лето → летом
• осень → осенью

This is one of the standard ways Russian expresses when something happens.

The endings differ because the nouns belong to different declension types:

• лето is a neuter noun ending in -о, so instrumental singular is -ом
• осень is a feminine noun ending in a soft sign -ь, so instrumental singular is -ью

So:

• лето → летом
• осень → осенью

Because they are direct objects, so they are in the accusative case.

The verbs are:

• собирать / собираем = to gather, pick
• печь / печёт = to bake

What do we pick? черешню
What does grandma bake? тыкву

Both черешня and тыква are feminine nouns ending in -а / -я, so in the singular accusative they usually change to -у / -ю:

• черешня → черешню
• тыква → тыкву

That is why the sentence does not use the dictionary forms.

Because the adjective has to agree with the noun it describes in gender, number, and case.

Here, тыкву is:

• feminine
• singular
• accusative

So сладкий must also become feminine singular accusative:

• masculine: сладкий
• feminine nominative: сладкая
• feminine accusative: сладкую

So:

• сладкая тыква = sweet pumpkin (subject form / dictionary-like phrase)
• печёт сладкую тыкву = bakes sweet pumpkin

Because бабушка is the subject of the second clause, not the object.

In:

• осенью бабушка печёт сладкую тыкву

бабушка is the person doing the action, so it stays in the nominative case.

Compare:

• Бабушка печёт тыкву. = Grandma bakes pumpkin.
  (бабушка = subject, nominative)

• Мы любим бабушку. = We love grandma.
  (бабушку = object, accusative)

So in your sentence:

• бабушка = subject
• тыкву = object

А often links two ideas by contrast or comparison, but not necessarily strong opposition.

Here:

• Летом мы собираем черешню, а осенью бабушка печёт сладкую тыкву.

This feels like:

• In summer we pick sweet cherries, while in autumn grandma bakes sweet pumpkin.

Why not и?

• и just means and, simple addition.

Why not но?

• но means but, usually a stronger contradiction.

So а is perfect when you are setting one scene against another:

• summer vs autumn
• we vs grandma
• picking vs baking

It is often translated as and, while, or sometimes but, depending on context.

Because the subjects are different.

• мы собираем = we gather/pick
• бабушка печёт = grandma bakes

Russian verbs change depending on the subject:

From собирать:

• я собираю
• мы собираем

From печь:

• я пеку
• она / бабушка печёт
• мы печём

So the sentence uses:

• собираем because the subject is мы
• печёт because the subject is бабушка

Because Russian present tense is often used for habitual, regular, or customary actions.

So this sentence does not mean that the actions are happening right this second. It means something like:

• In summer we usually pick sweet cherries, and in autumn grandma bakes sweet pumpkin.

This is very natural in Russian, just as in English you can say:

• In winter we drink a lot of tea.
• On Sundays she goes to church.

The present tense describes a pattern or repeated behavior.

They are imperfective because the sentence describes habitual/repeated seasonal activities, not one completed event.

• собирать = to gather / pick (imperfective)
• печь = to bake (imperfective)

If you used perfective verbs, the sentence would sound more like a specific completed action or a one-time event, which does not fit the general seasonal meaning as well.

In this sentence, the idea is:

• every summer / generally in summer → we pick cherries
• every autumn / generally in autumn → grandma bakes pumpkin

That is a classic context for the imperfective.

This is a very common vocabulary question.

• черешня = sweet cherry
• вишня = sour cherry / tart cherry

In English both may simply be called cherry, but Russian distinguishes them clearly.

So собирать черешню suggests picking the sweeter kind, the kind often eaten fresh.

The verb is pronounced печёт with yo sound: pechyot.

Russian ё is sometimes written as е in ordinary text, so you may also see:

• печет

But the correct pronunciation is still печёт, not печет with plain e.

This matters because ё always carries stress:

• печёт

For learners, it is very helpful when ё is written explicitly.

The word order is natural, but not completely fixed.

Russian word order is more flexible than English because case endings show grammatical roles.

This sentence starts with time expressions:

• Летом
• осенью

That gives a nice contrast: In summer..., and in autumn...

You could also say, for example:

• Мы летом собираем черешню, а бабушка осенью печёт сладкую тыкву.

This is still grammatical, but the focus changes slightly. The original version sounds smoother and more balanced because it highlights the seasonal contrast first.

Because Russian often uses a noun instead of a pronoun when it is clearer or more natural.

The sentence could theoretically have a pronoun in some contexts, but бабушка is more specific and sounds better here:

• Летом мы собираем черешню, а осенью бабушка печёт сладкую тыкву.

This gives a clear contrast:

• we
• grandma

Russian does not always repeat pronouns the same way English does. Very often, using the noun is more natural than replacing it with она.

Yes. Grammatically, тыкву means pumpkin, not pumpkin pie.

So:

• бабушка печёт сладкую тыкву = grandma bakes sweet pumpkin

It refers to the pumpkin itself as food. If Russian wanted to say pumpkin pie, it would use a different noun phrase, such as something involving пирог.

So the object here is literally pumpkin.

A careful pronunciation guide would be something like:

Lyetam my sobirayem cheryeshnyu, a osenyu babushka pyechyot sladkuyu tykvu.

A few helpful points:

• Летом → stress on the first syllable: ЛЕтом
• собираем → sabiRAyem
• черешню → stress on -ре-: cheRYESHnyu
• осенью → Osenyu
• печёт → peCHYOT
• сладкую → SLATkuyu
• тыкву → stress on the first syllable: TYKvu

The comma before а also suggests a natural pause:

• Летом мы собираем черешню, | а осенью бабушка печёт сладкую тыкву.