Learn Hardcore Russian: Бухгалтер проверяет финансовые отчёты каждый месяц. - The accountant checks the financial reports every month.

Russian does not have articles like English the or a/an. Definiteness and indefiniteness are understood from context, word order or additional words. In this sentence, you know which accountant we’re talking about from the situation, so no article is needed.

Why is проверяет used here (present tense) if the action happens each month?

In Russian, the present tense of an imperfective verb (like проверять) can express habitual or repeated actions (“every month”). If you said проверяет, it means “checks habitually/regularly.” A perfective form (проверит) would refer to a single completed action in the future, not a repeated one.

What is the form проверяет, grammatically?

Проверяет is the 3rd person singular present tense of the imperfective verb проверять (to check). Its full conjugation in present tense is:

я проверяю
ты проверяешь
он/она проверяет
мы проверяем
вы проверяете
они проверяют

Why do финансовые and отчёты both end in -ые and -ы, respectively?

They form a direct object in the accusative plural. Since отчёты (reports) is an inanimate masculine noun, its accusative plural matches the nominative plural. Thus:

Nominative plural: финансовые отчёты
Accusative plural: финансовые отчёты
The adjective финансовые agrees in gender (m.), number (pl.), and case (acc./nom. pl.).

Why is the letter ё used in отчёты instead of е?

The letter ё denotes the sound “yo” and is always stressed. In many printed texts Russians drop the two dots and write е, but for learners the dots show you must pronounce it as /ɐtˈtʃɵtɨ/ (“otch-YO-ty”).

What grammatical role does каждый месяц play, and what case is it?

Каждый месяц is an adverbial expression of time meaning “each month” or “every month.” Grammatically, it’s in the accusative case, which Russian often uses for duration or frequency expressions (questions “когда?” / “how often?”). You could also use the adverb ежемесячно in its place.

Can I replace каждый месяц with ежемесячно? Are there any differences?

Yes.

Бухгалтер ежемесячно проверяет…
Both sentences mean “The accountant checks … every month.”
Каждый месяц is a two-word time phrase, while ежемесячно is a single adverb. The difference is only stylistic.

Does бухгалтер change if the accountant is female?

No. The job title бухгалтер is common for both men and women. Colloquial forms like бухгалтерша exist but are outdated or slightly derogatory. Professionals simply say бухгалтер.

Could I change the word order? For example, start with Каждый месяц?

Absolutely. Russian is flexible:

Каждый месяц бухгалтер проверяет финансовые отчёты. (emphasizes frequency)
Бухгалтер проверяет каждый месяц финансовые отчёты. (more neutral)
All are correct; you shift emphasis by moving elements around.