אם העיניים שלך עייפות והאוזניים כואבות, אולי את צריכה לנוח היום.

Because the sentence is addressed to a female singular person.

In Hebrew, you changes by gender in the singular:

• אתה = you to a male
• את = you to a female

And the adjective/predicate that goes with it also changes:

• צריך = needing / need to, masculine singular
• צריכה = needing / need to, feminine singular

So:

• את צריכה לנוח = you (female) need to rest
• אתה צריך לנוח = you (male) need to rest

This is one of the most important differences from English, where you does not show gender.

Because they describe העיניים and האוזניים, and those nouns are feminine plural.

In Hebrew, adjectives usually agree with the noun in:

• gender
• number
• sometimes definiteness in structure, though not by special adjective marking

Here:

• העיניים = the eyes → feminine plural
• עייפות = tired → feminine plural

and

• האוזניים = the ears → feminine plural
• כואבות = hurting / painful → feminine plural

So the agreement is exactly what Hebrew grammar requires.

Because the nouns themselves are grammatically feminine:

• עין = eye, feminine
• אוזן = ear, feminine

When pluralized:

• עיניים = eyes
• אוזניים = ears

Since both nouns are feminine, any adjective describing them must also be feminine plural, which is why you get עייפות and כואבות.

This is grammatical gender, not biological gender.

Yes, ־יים is historically the dual ending in Hebrew, often used for things that naturally come in pairs.

Common examples:

• עין → עיניים = eyes
• אוזן → אוזניים = ears
• יד → ידיים = hands
• רגל → רגליים = legs

For many body parts that come in pairs, modern Hebrew usually uses this form where English simply uses a normal plural.

Even though the form is historically dual, in modern Hebrew it generally behaves grammatically like a plural, so the adjectives are plural:

• העיניים עייפות
• האוזניים כואבות

Because שלך here means your for one person, and in this form it can refer to either a male or a female addressee depending on context.

Hebrew possessive forms with של work like this:

• שלי = my
• שלך = your (singular)
• שלו = his
• שלה = her
• שלנו = our
• שלכם / שלכן = your (plural)
• שלהם / שלהן = their

In everyday modern Hebrew, שלך is used for singular your, and the gender of the person addressed is often understood from the rest of the sentence.

In this sentence, we know the addressee is female because of את צריכה.

It comes from the verb לכאוב = to hurt / to ache, but in sentences like this it behaves like a present-tense participle, which often works much like an adjective in Hebrew.

So:

• האוזניים כואבות = the ears hurt / the ears are hurting

This is similar to other Hebrew present forms that can feel halfway between a verb and an adjective.

You can think of כואבות here as:

• grammatically: a feminine plural present form
• functionally: hurt / are hurting

Because האוזניים is feminine plural, the form must be כואבות.

Other forms would be:

• כואב = masculine singular
• כואבת = feminine singular
• כואבים = masculine plural
• כואבות = feminine plural

Because in the present tense, Hebrew usually does not use a separate word for am / is / are.

So Hebrew often says literally:

• העיניים שלך עייפות = your eyes tired
• האוזניים כואבות = the ears hurting / hurt

But in natural English, we translate with are:

• your eyes are tired
• your ears hurt / are hurting

This is a major difference from English. In present-tense nominal/adjectival sentences, Hebrew typically leaves out the verb to be.

אם means if.

So the sentence structure is:

• אם ... , אולי ...
• If ... , maybe ...

Here:

• אם העיניים שלך עייפות והאוזניים כואבות = If your eyes are tired and your ears hurt
• אולי את צריכה לנוח היום = maybe you should/need to rest today

This is a very common Hebrew way to build a conditional sentence.

Yes, אולי usually means maybe or perhaps.

In this sentence it softens the statement:

• את צריכה לנוח היום = you need to rest today
• אולי את צריכה לנוח היום = maybe you need to rest today / maybe you should rest today

In English, depending on tone, this sentence may sound closer to maybe you should rest today rather than a strict need.

So אולי adds tentativeness and makes the advice gentler.

Because in real usage, צריך / צריכה can express a range of meanings depending on context:

• need to
• have to
• sometimes should

So:

• את צריכה לנוח can mean:
  • you need to rest
  • you should rest

In this sentence, because of אולי, the overall tone is softer and more like advice, so English often prefers maybe you should rest today.

Literal grammar and natural translation are not always identical.

לנוח is the infinitive to rest.

The base verb is נח / לנוח.

After צריך / צריכה, Hebrew usually uses an infinitive:

• אני צריך ללכת = I need to go
• היא צריכה לאכול = she needs to eat
• את צריכה לנוח = you need to rest

So the pattern is:

• [person] + צריך/צריכה + infinitive

Because Hebrew word order is flexible, and placing היום at the end is completely natural.

• אולי את צריכה לנוח היום = Maybe you need to rest today

You could also hear:

• אולי היום את צריכה לנוח

That shifts the emphasis slightly toward today.

The original sentence sounds very normal and neutral.

Yes. Only the part referring to the person being addressed would change.

Original, to a woman:

• אם העיניים שלך עייפות והאוזניים כואבות, אולי את צריכה לנוח היום.

To a man:

• אם העיניים שלך עייפות והאוזניים כואבות, אולי אתה צריך לנוח היום.

Notice:

• את → אתה
• צריכה → צריך

But these parts stay the same:

• העיניים שלך עייפות
• והאוזניים כואבות

That is because eyes and ears are still feminine plural nouns no matter who is being addressed.

That ו is simply the Hebrew word and attached as a prefix.

So:

• ו = and
• האוזניים = the ears
• והאוזניים = and the ears

Hebrew often attaches short function words directly to the following word, instead of writing them separately.

It is natural Hebrew.

The structure is very normal:

• אם
  • condition
• description of symptoms
• אולי
  • suggestion/advice
• את צריכה
  • infinitive

So the sentence flows naturally as:

• If your eyes are tired and your ears hurt, maybe you should rest today.

Nothing in it sounds artificially translated from English.