Я пишу лист ручкою.

I write a letter with a pen.

Breakdown of Я пишу лист ручкою.

• я: I
• ручка: the pen
• писати: to write
• лист: the letter

Questions & Answers about Я пишу лист ручкою.

Why is ручкою used here instead of ручка?

Ручкою is the instrumental case of the feminine noun ручка. Ukrainian uses the instrumental case (usually ending in -ою for feminine nouns like ручка → ручкою) to show the tool or means by which an action is done. English uses “with a pen,” but Ukrainian simply changes the noun ending.

What case is лист in, and why doesn’t it change form?

Лист is in the accusative case as the direct object. Since лист is a masculine inanimate noun, its accusative form is identical to the nominative (лист).

Why do we include я if пишу already indicates “I”?

Ukrainian is a pro-drop language: the verb ending -у in пишу shows first-person singular, so you can omit я. You add я only for emphasis or clarity (e.g. contrasting who does the action).

Does пишу mean “I write” or “I am writing”? How do you say “I am writing”?

Ukrainian doesn’t distinguish simple vs. progressive in the verb form. Пишу can mean either “I write” (habitually) or “I am writing” (right now). To stress “right now,” you can add зараз:
Я зараз пишу лист ручкою.

Can the word order change? For example, Ручкою я пишу лист?

Yes. Ukrainian has flexible word order because cases mark roles. The neutral order is S-V-O plus instrument last: Я пишу лист ручкою. Moving ручкою or я to the front shifts emphasis onto that element.

How is ру́чкою pronounced and where is the stress?

• я [ja]
• пишу [py-SHU] (stress on шу)
• лист [lyst] (one syllable)
• ручкою [RUCH-ko-yu] (stress on the first syllable руч; -ою sounds like “o-yu”)

Why don’t we use a preposition like in English (“with”)?

Instead of a preposition, Ukrainian expresses instruments directly by the instrumental case ending. You rarely need a preposition for “with” in this sense. For emphasis you could say за допомогою ручки, but ручкою is far more common.