אם משהו חסר ברשימה, תוסיפי אותו לפני שאת יוצאת.

Because the sentence is addressed to one female person.

• תוסיפי = you should add / add (to one woman)
• את יוצאת = you are leaving / you leave (again, to one woman)

If you were speaking to a man, you would say:

• אם משהו חסר ברשימה, תוסיף אותו לפני שאתה יוצא.

So the verb forms in the sentence agree with a feminine singular you.

In spoken and everyday Hebrew, people often use the future tense to give instructions or commands, especially with you forms.

So:

• תוסיפי literally looks like future: you will add
• but in context it means: add it

A more strictly imperative feminine singular form would be הוסיפי, but that sounds more formal, literary, or old-fashioned in many everyday situations.

So in normal modern Hebrew, תוסיפי is very natural.

Here חסר means missing or lacking.

So:

• משהו חסר = something is missing

It is functioning like an adjective or predicate, not as a past-tense verb.

You can compare:

• יש משהו חסר = there is something missing
• השם חסר ברשימה = the name is missing from the list

Because משהו is grammatically masculine, the word is חסר and not חסרה.

Literally, ברשימה means in the list, because ב־ usually means in / at / on, depending on context.

In English, we usually say on the list, but Hebrew commonly says ברשימה.

So:

• חסר ברשימה = missing from/on the list

This is a good example of a preposition that does not match English exactly.

Because it refers back to משהו, and משהו is grammatically masculine.

So:

• משהו = something
• אותו = it / him (masculine direct object)

In this sentence, אותו means it, not him.

Hebrew object pronouns reflect grammatical gender, even when English just says it.

If the noun being referred to were feminine, you would use אותה.

אותו is the direct object pronoun: it.

The phrase:

• תוסיפי אותו = add it

Hebrew often uses a separate object pronoun after the verb, where English also uses it after the verb.

So the structure is very straightforward:

• תוסיפי = add
• אותו = it

אם means if.

So the sentence has a conditional structure:

• אם משהו חסר ברשימה = if something is missing from the list
• תוסיפי אותו = add it

This is a very common Hebrew pattern:

• אם..., then instruction/result

Just like English, the if clause sets up the condition.

Literally, it means before that you leave / before you are leaving.

More naturally in English:

• before you leave

Breaking it down:

• לפני = before
• ש־ = that
• את = you (feminine singular)
• יוצאת = going out / leaving

So Hebrew uses a full clause after לפני, where English just says before you leave.

It really is two parts:

• ש־ = that
• את = you (feminine singular)

They are simply written together as שאת.

This happens very often in Hebrew:

• שאני = that I
• שאתה = that you (masculine)
• שאת = that you (feminine)
• שהוא = that he

So לפני שאת יוצאת is literally before that-you leave.

This is a very common Hebrew feature.

Hebrew often uses the present tense after time words like when, before, or after, especially when talking about something expected or imminent.

So:

• לפני שאת יוצאת literally looks like before you are going out
• but naturally means before you leave

In many contexts, present tense in Hebrew covers ideas that English might express with the present or future.

A slightly different version you may also hear is:

• לפני שתצאי

That also means before you leave, but the version in your sentence is perfectly natural.

It can mean either, depending on context.

The verb לצאת basically means to go out / to exit / to leave.

In this sentence:

• לפני שאת יוצאת

could be understood as:

• before you leave
• before you go out

Because the earlier part talks about a list, English often translates it as before you leave, but the Hebrew verb itself is the ordinary verb to go out / leave.

The neutral, standard word order is:

• verb + object
• תוסיפי אותו = add it

You can say אותו תוסיפי in some contexts, but that would add emphasis, something like:

• add that
• it is that which you should add

So in this sentence, תוסיפי אותו is the normal, unmarked order.

Yes, משהו is normally treated as a masculine singular noun in grammar.

That is why the sentence has:

• משהו חסר
• אותו

not:

• משהו חסרה
• אותה

This is useful to remember because even though something in English has no gender, Hebrew still assigns grammatical gender to it.

Here are the common versions:

To one man:

• אם משהו חסר ברשימה, תוסיף אותו לפני שאתה יוצא.

To one woman:

• אם משהו חסר ברשימה, תוסיפי אותו לפני שאת יוצאת.

To more than one person:

• אם משהו חסר ברשימה, תוסיפו אותו לפני שאתם יוצאים.
• or to a group of women:
• אם משהו חסר ברשימה, תוסיפו אותו לפני שאתן יוצאות.

So the main changes are in the you forms of the verbs and pronouns.

A simple pronunciation guide is:

Im mashehu chaser ba-r'shima, tosifi oto lifnei she'at yotzet.

A few notes:

• אם = im
• משהו = mashehu
• חסר = chaser
• ברשימה = ba-r'shima
• תוסיפי = tosifi
• אותו = oto
• לפני = lifnei
• שאת = she'at
• יוצאת = yotzet

The stress is commonly:

• maSHEhu
• chaSER
• r'shiMA
• toSIfi
• oTO
• lifNEI
• yoTZET