Learn Hardcore Russian: Учитель объясняет инфинитив студентам. - The teacher explains the infinitive to the students.

In Russian, the verb объяснять (to explain) is ditransitive: it takes a direct object (what is being explained) in the accusative and an indirect object (to whom it is explained) in the dative. Here студентам (students) answers the question кому? (to whom?), so it must be in the dative plural.

Why is инфинитив in the accusative case?

Инфинитив (infinitive) is the direct object of объясняет, answering что? (what?). Because it’s an inanimate masculine noun in the singular, its nominative and accusative forms coincide as инфинитив.

What objects does the verb объяснять require, and how do I recognize them?

Объяснять requires two objects:
1) A direct object in the accusative (что? – инфинитив)
2) An indirect object in the dative (кому? – студентам)
You spot them by asking the questions что? for the thing explained and кому? for the person receiving the explanation.

How would I form студентам from студент?

Студент is a masculine noun. To make it plural, you change it to студенты (nominative plural). Then switch to the dative plural ending -ам, giving студентам.

Can I change the word order in “Учитель объясняет инфинитив студентам”?

Yes. Russian has flexible word order for emphasis. All these are correct:

Учитель студентам объясняет инфинитив. (emphasizes студентам)
Инфинитив учитель студентам объясняет. (emphasizes инфинитив)
Студентам учитель объясняет инфинитив.
Yet the default neutral order is Subject–Verb–Direct Object–Indirect Object.

Why are there no articles (a, the) before инфинитив or студентам?

Russian doesn’t use definite or indefinite articles. Context alone tells you if you mean “the infinitive” or “an infinitive,” and whether you mean “to students” in a general sense.

How is объясняет pronounced, and where is the stress?

Break it down as об- / яс- / няет with the stress on the яс syllable. You’ll hear it like “ob-YAS-nyayet.”

Could I say Учитель объясняет для студентов инфинитив instead?

This would sound unnatural. Для студентов means “for the students,” which slightly shifts the meaning toward purpose (“in order to help students”). The correct government for объяснять is without a preposition: direct object in accusative and indirect object in dative.