הטוש השחור לא עובד, אז אני אכתוב בטוש אדום.

In Hebrew, adjectives usually come after the noun they describe.

So:

• הטוש השחור = the black marker
• literally: the marker the-black

This is the normal word order in Hebrew:

• ספר מעניין = an interesting book
• ילדה קטנה = a small girl

So טוש שחור is the natural way to say black marker.

Because when a noun is definite in Hebrew, its adjective usually becomes definite too.

So:

• טוש שחור = a black marker
• הטוש השחור = the black marker

Hebrew marks definiteness with ה־ on both the noun and the adjective in this kind of phrase.

That is why you see:

• הטוש = the marker
• השחור = the black

Together: הטוש השחור = the black marker

Because here the speaker means with a red marker, not with the red marker.

So this phrase is indefinite:

• בטוש אדום = with a red marker

If you said:

• בטוש האדום

that would mean:

• with the red marker

So the difference is:

• טוש אדום = a red marker
• הטוש האדום = the red marker

טוש usually means a marker or felt-tip pen.

Depending on context, English might translate it as:

• marker
• felt-tip pen
• sometimes pen in a looser translation

In this sentence, marker is the best match.

Yes, עובד literally means works, and Hebrew uses it for objects too.

So:

• הטוש השחור לא עובד = the black marker doesn't work

This is very natural in Hebrew, just like English says:

• My phone doesn't work
• The printer isn't working

Since טוש is grammatically masculine singular, the form is עובד.

If the noun were feminine singular, you would often see עובדת instead.

Hebrew often uses the present tense form plus לא to say that something does not happen in the present.

So:

• עובד = working / works
• לא עובד = doesn't work / isn't working

Hebrew present tense does not have a separate word for does like English does.

Compare:

• הוא עובד = he works / he is working
• הוא לא עובד = he doesn't work / he isn't working

The exact English translation depends on context.

אז here means so.

In this sentence:

• הטוש השחור לא עובד, אז אני אכתוב בטוש אדום.
• The black marker doesn't work, so I'll write with a red marker.

It connects cause and result.

Depending on context, אז can also mean then, but here so is the most natural translation.

Because אכתוב is the first person singular future form of the verb לכתוב (to write).

The root is כ־ת־ב, which is connected with writing.

In future tense:

• אכתוב = I will write
• תכתוב = you will write / she will write
• יכתוב = he will write

The prefix א־ often marks I in the future tense.

So אני אכתוב literally means I will write.

Yes, in many cases אני is optional, because אכתוב already tells you the subject is I.

So Hebrew could say:

• אז אכתוב בטוש אדום

and that would still mean:

• So I'll write with a red marker

However, אני is often included for clarity, emphasis, or just natural rhythm.

So both are possible:

• אז אני אכתוב בטוש אדום
• אז אכתוב בטוש אדום

The version with אני can feel a little more explicit.

Yes. The preposition ב־ usually means in, at, or with/by means of, depending on context.

Here it shows the instrument used for writing:

• בטוש אדום = with a red marker

This is very normal in Hebrew. Hebrew often uses ב־ where English uses with for tools or means.

For example:

• לכתוב בעיפרון = to write with a pencil
• לחתוך בסכין = to cut with a knife

So ב־ here means something like using.

Because Hebrew prepositions like ב־ often attach directly to the following word as a prefix.

So:

• ב
  • טוש = בטוש

This is completely normal.

The same thing happens with other short prepositions:

• ל
  • ספר = לספר = to a book / to tell depending on context
• כ
  • ילד = כילד = as a child

When the noun is definite, the form can change a little more:

• ב
  • הטוש becomes בטוש in standard spelling, with the definiteness understood through the form

But in your sentence, בטוש אדום is indefinite anyway: with a red marker.

Because adjectives in Hebrew must agree with the noun in gender and number.

טוש is masculine singular, so the adjectives are also masculine singular:

• שחור = black (masculine singular)
• אדום = red (masculine singular)

If the noun were feminine singular, the forms would usually change:

• שחורה
• אדומה

So the sentence uses:

• הטוש השחור
• בטוש אדום

because טוש is masculine singular in both places.

Yes, in some contexts Hebrew speakers might avoid repeating it if the meaning is obvious, but the sentence as written is very natural and clear.

For example, you might hear something shorter in conversation, but:

• הטוש השחור לא עובד, אז אני אכתוב בטוש אדום

is straightforward and idiomatic.

Repeating טוש makes it completely clear that the speaker is switching from one marker to another.