כשאני רואה את החיוך שלה, אני יודעת שהיא אוהבת את העוגה ואת הבלונים.

כשאני means when I.

It is made from:

• כש־ = when
• אני = I

So כשאני רואה... means when I see...

A longer, more formal version is כאשר אני. In everyday Hebrew, כש־ is much more common.

Because the speaker is female.

In Hebrew, the present tense often agrees with the gender of the subject:

• אני יודעת = I know said by a woman
• אני יודע = I know said by a man

So this sentence is being spoken by a female speaker.

Because Hebrew is usually written without vowel marks, so some masculine and feminine forms can look identical in writing.

Here:

• רואה can be read as ro'ah for a female speaker
• רואה can also be read as ro'eh for a male speaker

The context tells you which one it is. Since the sentence later has אני יודעת, we know the speaker is female, so רואה here is understood as the feminine pronunciation.

Here, את is the direct object marker. It does not mean you in this sentence.

Hebrew uses את before a definite direct object—usually something with the, a name, or a possessive expression.

So:

• את החיוך שלה
• את העוגה
• את הבלונים

all take את because they are definite.

English has no equivalent word, so את is usually not translated.

No. Although את can mean you when speaking to one female, that is not what it means here.

You can tell from the grammar:

• after רואה את... it introduces the object being seen
• after אוהבת את... it introduces the thing being loved

So in this sentence, every את is the direct object marker.

Because Hebrew often repeats את before each definite object in a list.

So:

• את העוגה ואת הבלונים

is a normal, clear way to say the cake and the balloons as direct objects.

You may also hear less repetition in casual speech, but repeating את is very standard and often preferred.

This is a very common Hebrew way to show possession:

• החיוך = the smile
• שלה = hers / her

So החיוך שלה literally means the smile of hers, but in natural English that is just her smile.

Hebrew often uses this pattern:

• noun + שלי / שלך / שלה / שלו etc.

There is also a shorter, more literary form:

• חיוכה = her smile

But החיוך שלה is very common and natural.

Because it combines:

• ש־ = that
• היא = she

So:

• אני יודעת שהיא אוהבת...
• I know that she loves...

This ש־ is very common in Hebrew for introducing a subordinate clause.

Because the subject is היא = she.

In the present tense, Hebrew verbs agree with gender:

• היא אוהבת = she loves
• הוא אוהב = he loves

So אוהבת is feminine singular, matching היא.

Because ה־ is the Hebrew definite article, meaning the.

So:

• החיוך = the smile
• העוגה = the cake
• הבלונים = the balloons

In Hebrew, the is attached directly to the noun as a prefix, instead of being a separate word like in English.

Hebrew usually keeps ש־ here.

English often says either:

• I know that she loves...
• I know she loves...

But in Hebrew, אני יודעת שהיא אוהבת... is the normal form. Leaving out ש־ would usually sound unnatural here.

So in this kind of sentence, it is best to keep ש־.

The comma separates the opening when clause from the main clause:

• כשאני רואה את החיוך שלה,
• אני יודעת...

This works much like English punctuation in a sentence such as When I see her smile, I know...

In Hebrew, comma usage can vary a bit, but this comma is natural and helpful.