По её взгляду кто угодно поймёт, что она устала.

Here по + dative case means something like judging by, from, or by.

So по её взгляду means:

• by her look
• judging by her expression
• from the way she looks

This is a very common Russian pattern:

• по голосу = by the voice
• по лицу = by the face / expression
• по походке = by the walk / gait

So the sentence is built around the idea from her look, anyone will understand...

Because the preposition по often requires the dative.

The base form is взгляд.
Its dative singular form is взгляду.

So:

• взгляд = look, glance
• по взгляду = by the look / judging by the look

And since её does not change form here, the full phrase is:

• по её взгляду

In this sentence, взгляд is best understood as look, expression, or the way she is looking.

Russian взгляд can mean:

• a glance
• a look
• someone’s expression in the eyes

Here it is not just one quick glance. It is more like the look in her eyes / on her face that shows she is tired.

So English translations like these all work depending on context:

• By her look, anyone can tell she’s tired.
• Judging by her expression, anyone would understand that she is tired.
• From the look in her eyes, anyone will understand she’s tired.

Кто угодно means anyone, anybody, or sometimes whoever you like depending on context.

In this sentence:

• кто угодно поймёт = anyone will understand / anyone can tell

This expression is made from:

• кто = who
• угодно = literally something like it pleases / you like, but in modern usage it helps create an indefinite free-choice meaning

Other similar expressions are:

• что угодно = anything
• где угодно = anywhere
• когда угодно = anytime
• какой угодно = any kind of

Good question. Russian often uses the future perfective where English uses a more general present like can tell or will understand.

Поймёт is the future form of the perfective verb понять (to understand, to realize).

So кто угодно поймёт literally means:

• anyone will understand

But in natural English, depending on context, it may be better translated as:

• anyone can tell
• anyone would understand
• anyone will understand

Russian perfective future often gives the sense of a complete result: once someone sees her expression, they will immediately come to that conclusion.

Because поймёт focuses on the moment of coming to understand.

Compare:

• понимать = to understand, to be understanding
• понять = to understand, to grasp, to realize

In this sentence, the idea is not anyone is understanding in a general ongoing sense. It is:

• someone looks at her
• they grasp the fact
• they realize she is tired

That is why the perfective verb понять is more natural here.

So:

• кто угодно поймёт = anyone will realize / anyone can tell

Устала is the past tense feminine singular form of the verb устать (to get tired / to become tired), but in Russian this form often functions like is tired in context.

So:

• она устала = she got tired / she is tired

In many cases, English uses an adjective (tired), while Russian often uses this past-tense verb form.

Compare:

• Она устала. = She is tired.
• Она уставшая. = She is tired-looking / she’s in a tired state / she’s a tired person right now
• Она усталая. = She is tired (adjectival description), but this can sound more descriptive than the very common она устала

In everyday Russian, она устала is the most normal way to say she is tired.

Because что она устала is a subordinate clause.

The main clause is:

• По её взгляду кто угодно поймёт = By her look anyone will understand

The subordinate clause is:

• что она устала = that she is tired

Russian normally separates subordinate clauses with a comma, especially before что when it means that.

So the structure is:

• [main clause], [subordinate clause]

Yes, Russian word order is flexible, and this phrase is placed first for emphasis or framing.

Starting with По её взгляду highlights the source of the conclusion:

• Judging by her look...

Other word orders are possible, for example:

• Кто угодно поймёт по её взгляду, что она устала.
• Что она устала, кто угодно поймёт по её взгляду.

But the original version sounds natural because it sets up the basis first:

• By her look, anyone will understand...

This is very common in Russian: important contextual information often comes at the beginning.

Её means her.

It can be:

• a possessive form: her
• an object form: her

Here it is possessive:

• её взгляд = her look
• по её взгляду = by her look

Unlike many other Russian words, её does not change form in the standard language. So even though взгляду is dative, её stays её.

Yes — that is probably one of the most natural English translations.

A very literal version is:

• By her look, anyone will understand that she is tired.

But more natural English might be:

• Anyone can tell from her expression that she’s tired.
• Anyone can see from the look on her face that she’s tired.
• Judging by her expression, it’s obvious she’s tired.

So the Russian sentence is straightforward, but natural English usually prefers can tell or can see.

Её is pronounced roughly yi-YO.

The letter ё is important for pronunciation because it shows the stressed yo sound.

So:

• ее is often written instead of её in ordinary texts
• but it is still usually meant to be pronounced её

In learner materials, writing ё is very helpful. In native texts, people often omit the dots and write ее, but the intended word is still usually clear from context.

In this sentence, её is the standard learner-friendly spelling.