Learn Hardcore Russian: Мама гладит рубашку утюгом.

Рубашка is in the accusative singular because it is the direct object of гладить. Feminine nouns ending in –а change to –у in the singular accusative.

What case is утюгом in and why?

Утюг is in the instrumental singular (–ом) because the instrumental case indicates the tool used to perform the action (“with an iron”).

Why is there no preposition for “with an iron”?

In Russian the instrumental case itself shows “with” when talking about instruments or tools. A separate preposition is not needed.

What does the verb гладить mean here, and does it have other meanings?

Here гладить means “to iron” clothes. It can also mean “to stroke/caress” animals or people (e.g., гладить кошку means “to pet a cat”). Context determines the meaning.

Why is the verb гладит imperfective, and how do you say “Mom has ironed the shirt”?

Гладит is imperfective, expressing an ongoing action (“is ironing”). The perfective counterpart is погладить. To say “Mom has ironed the shirt,” you would say Мама погладила рубашку утюгом.

How do you form the present tense of гладить for “she”?

Гладить conjugates: я глажу, ты гладишь, он/она/оно гладит, мы гладим, вы гладите, они гладят. Here гладит is the 3rd person singular form.

Where does the stress fall in гладит, and does it ever shift?

The stress is on the first syllable: ГЛАдит. It remains there in all present-tense forms of гладить.

Can I change the word order, for example, put утюгом first?

Yes. Russian word order is fairly flexible. Утюгом мама гладит рубашку is correct, and it emphasizes the tool more.

How do you ask “With what is Mom ironing the shirt?” in Russian?

Use the instrumental question word чем: Чем мама гладит рубашку?