Налогоплательщик выбрал налоговый вычет.

It is the subject of the sentence, so it is in the nominative case.

In Russian, the subject is usually in the nominative, just like in this sentence: Налогоплательщик выбрал налоговый вычет.

Also, налогоплательщик is a masculine noun, and in the nominative singular many masculine nouns have no visible ending after the final consonant.

Выбрал is the past tense, singular, masculine form of the verb.

So this one form already tells you several things:

• past action
• one subject
• masculine grammatical agreement

Russian past tense verbs agree with the subject in gender and number:

• выбрал — masculine singular
• выбрала — feminine singular
• выбрало — neuter singular
• выбрали — plural

Unlike English, Russian does not need an extra auxiliary like did to form the past tense here.

The dictionary form is выбрать.

This verb is perfective, which means it presents the action as completed: the choice was made.

Its imperfective partner is выбирать. Compare:

• выбрал — chose / has chosen, with the result in view
• выбирал — was choosing / used to choose / chose, with focus on process or repeated action

So in this sentence, выбрал suggests a completed selection.

Because it is the direct object of the verb выбрать, and выбрать normally takes the accusative case.

So:

• налогоплательщик — subject, nominative
• налоговый вычет — direct object, accusative

This is very normal Russian sentence structure.

Because вычет is an inanimate masculine singular noun.

For inanimate masculine singular nouns, the accusative form is usually the same as the nominative form. So:

• nominative: налоговый вычет
• accusative: налоговый вычет

If the noun were animate, the form would often match the genitive instead.

Because adjectives in Russian must agree with the noun they modify in:

• gender
• number
• case

Here, налоговый describes вычет, which is:

• masculine
• singular
• accusative (but identical in form to nominative here)

So the adjective also appears in the matching masculine singular form: налоговый вычет.

Because they are both built from the noun налог meaning tax.

But they function differently:

• налогоплательщик is a compound noun meaning taxpayer
• налоговый is an adjective meaning tax-related or tax

So even though both words are related to налог, one is a noun and the other is an adjective.

You do not know from the Russian sentence alone, because Russian has no articles like the and a/an.

Context decides it. Depending on the situation, the sentence could correspond to:

• the taxpayer chose the tax deduction
• the taxpayer chose a tax deduction
• a taxpayer chose the tax deduction
• a taxpayer chose a tax deduction

In real usage, surrounding context usually makes this clear.

No, Russian word order is fairly flexible, but this version is the most neutral and straightforward: subject + verb + object

So: Налогоплательщик выбрал налоговый вычет
is the neutral way to present the information.

Other orders are possible, but they change the emphasis or information structure, not the basic core meaning. For example:

• Налоговый вычет выбрал налогоплательщик — stronger focus on налоговый вычет
• Выбрал налоговый вычет налогоплательщик — marked, stylistic, or context-dependent

Yes. Russian perfective past often corresponds to either:

• the English simple past: chose
• or the English present perfect: has chosen

Which English version sounds best depends on context.

So выбрал does not by itself force only one English tense choice. It mainly tells you that the action is viewed as completed.

Yes. It is a compound word, and you can roughly break it down like this:

• налого- — a combining form related to налог
• плательщик — payer

So the whole word literally means something like tax-payer, which is why it corresponds to taxpayer in English.

Russian official and legal language often uses long compound words like this, so getting used to spotting their parts is very helpful.