Он ждал пятьдесят минут.

Ждал is the past tense, masculine singular form of the verb ждать (to wait).

So:

• я ждал / я ждала = I waited
• он ждал = he waited
• она ждала = she waited
• они ждали = they waited

Russian past tense agrees with the subject in gender and number, so with он you get ждал.

Because the sentence is in the past.

• ждёт = is waiting / waits (present tense)
• ждал = waited / was waiting (past tense)

So:

• Он ждёт пятьдесят минут would mean He has been waiting for fifty minutes only in a limited context, but more literally it is He is waiting...
• Он ждал пятьдесят минут clearly places the action in the past: He waited for fifty minutes

Because Russian numerals control the form of the noun.

After numbers ending in 5–9, 0, and also after 11–14, the noun is normally in the genitive plural.

So:

• пять минут = five minutes
• десять минут = ten minutes
• пятьдесят минут = fifty minutes

That is why you get минут, which is the genitive plural form of минута.

Compare:

• одна минута
• две / три / четыре минуты
• пять минут
• пятьдесят минут

Because минуты is used after numbers ending in 2, 3, 4 (except 12, 13, 14).

For example:

• две минуты
• три минуты
• четыре минуты

But with пятьдесят, the last part is -десят, not 2, 3, or 4, so Russian uses минут instead.

Because Russian usually expresses duration without a preposition.

English says:

• He waited for fifty minutes

Russian simply says:

• Он ждал пятьдесят минут

This is very normal in Russian. Duration is often shown just by the numeral phrase itself.

Other examples:

• Я работал два часа = I worked for two hours
• Она спала десять часов = She slept for ten hours

So there is no missing word here.

This is one of those places where Russian works a little differently from English.

In sentences of duration, Russian often uses a time expression without a preposition. With numerals, the phrase has its own numeral pattern:

• пятьдесят is in the form used here for the whole expression
• минут is genitive plural because it follows a numeral like пятьдесят

So the important practical rule for learners is:

• after 5+, use genitive plural on the noun

You do not need to overcomplicate it at first. For speaking correctly, пятьдесят минут is simply the standard way to say fifty minutes here.

Because the sentence describes the process/duration of waiting, not a completed result as a single whole.

Ждать is imperfective, and it fits very naturally with expressions of duration such as пятьдесят минут.

• Он ждал пятьдесят минут = He was waiting / He waited for fifty minutes

Russian often uses the imperfective when focusing on:

• the action itself
• how long it lasted
• the ongoing process

A perfective verb would usually change the nuance.

Sometimes, yes, but it would change the meaning or tone.

For example:

• Он подождал usually means He waited a bit / waited for a while
• Он прождал пятьдесят минут can mean He spent fifty whole minutes waiting, often with a shade of annoyance or emphasis

So Он ждал пятьдесят минут is the most neutral way to say it.

Yes, often it can be, if the subject is already clear from context.

• Он ждал пятьдесят минут = He waited for fifty minutes
• Ждал пятьдесят минут = (He/I/someone masculine) waited for fifty minutes, depending on context

Russian often drops subject pronouns when they are not necessary, but learners usually include them more often at first, which is perfectly fine.

Yes. Russian word order is fairly flexible, although the neutral order here is:

• Он ждал пятьдесят минут

Other orders are possible for emphasis:

• Пятьдесят минут он ждал = It was fifty minutes that he waited
• Ждал он пятьдесят минут = more marked or stylistic

The basic meaning stays the same, but the emphasis changes.

It is stressed as пятьдеся́т.

A rough pronunciation guide:

• пятьдеся́т ≈ pyat-dee-SYAT

And:

• мину́т has stress on the second syllable: mee-NOOT

So the phrase is:

• Он ждал пятьдеся́т мину́т

It can be a little tricky for English speakers at first.

Ждал begins with a consonant cluster жд-. Try not to insert a vowel before it. It should sound roughly like:

• zhdal

Start with the ж sound (like the s in measure), then move quickly into д.

It may help to practice:

• жду
• ждал
• ждать

slowly first, then faster.

The dictionary forms are:

• он = he
• ждать = to wait
• пятьдесят = fifty
• минута = minute

In the sentence, ждать becomes ждал, and минута becomes минут because of the number.

Standard Russian requires минут after пятьдесят.

A native speaker would normally say:

• пятьдесят минут

Using минуты after пятьдесят would sound incorrect in standard Russian.

So this is a rule worth memorizing very firmly:

• 1 → минута
• 2–4 → минуты
• 5+ → минут

It can correspond to either, depending on context.

Russian past imperfective often covers both ideas:

• He waited for fifty minutes
• He was waiting for fifty minutes

English chooses between simple past and past continuous more often than Russian does. Russian ждал does not always force that distinction.

So in many contexts, the same Russian sentence can match either English version.