גם אם זה הרגל ישן, אני רוצה לשנות אותו.

A common pronunciation guide would be:

Gam im ze hergel yashan, ani rotze leshanot oto.

If the speaker is female, רוצה would be pronounced rotza instead of rotze:

Gam im ze hergel yashan, ani rotza leshanot oto.

So the writing stays the same, but the pronunciation can change depending on the speaker.

גם אם means even if.

• אם by itself means if
• גם by itself means also / even
• together, גם אם gives the idea even if

So this is introducing a concessive idea: something is true despite the fact that it is an old habit.

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

So:

• זה הרגל ישן literally looks like this/it old habit
• but it means it is an old habit

That is normal Hebrew grammar. Present-tense to be is usually just left out.

זה often means this or it / this is, depending on context.

In a sentence like זה הרגל ישן, זה is functioning like it is / this is. This is very common in everyday Hebrew.

A more formal version is זהו הרגל ישן, but זה הרגל ישן is perfectly normal in spoken Hebrew.

Without vowel marks, רוצה can be read either as:

• rotze = a male speaker saying I want
• rotza = a female speaker saying I want

This is very common in unpointed Hebrew: the spelling does not always show the gender clearly, but the context does.

Hebrew sometimes drops subject pronouns, but here אני is very helpful and usually expected.

The form רוצה by itself does not clearly show person in writing. It could mean:

• I want
• he wants
• she wants

So אני רוצה makes it clear that the speaker means I want.

Because in Hebrew, adjectives usually come after the noun.

So:

• הרגל ישן = an old habit
• literally: habit old

Also, the adjective must match the noun in gender and number.

Here:

• הרגל is masculine singular
• so the adjective is ישן, also masculine singular

If the noun were feminine, the adjective would change too. For example:

• בעיה ישנה = an old problem

לשנות is the infinitive, meaning to change.

The prefix ל־ often marks a Hebrew infinitive, similar to English to:

• לשנות = to change
• ללמוד = to learn
• לכתוב = to write

So אני רוצה לשנות means I want to change.

A useful extra note: without vowel marks, לשנות can represent more than one verb spelling-wise, but here the pronunciation is leshanot, meaning to change.

אותו here means it, referring back to הרגל.

So:

• לשנות אותו = to change it

Because הרגל is a masculine singular noun, the pronoun is also masculine singular:

• אותו = masculine singular direct object pronoun

If the noun were feminine, you would use אותה instead:

• אני רוצה לשנות אותה

Because אותו already functions as a direct object pronoun.

Compare:

• לשנות את ההרגל = to change the habit
• לשנות אותו = to change it

When you use a full definite noun like ההרגל, you need את. When you use a pronoun like אותו, you do not add a separate את before it.

Yes, you could, but there is a slight difference in feel.

• לשנות אותו directly refers back to הרגל
• לשנות את זה means change that / change it, and can sound a little less specifically tied to the noun

Since הרגל is masculine singular, אותו is the neatest and most grammatically linked choice here.

Both are correct, but they feel a little different.

• זה הרגל ישן = very natural in everyday speech
• זהו הרגל ישן = a bit more formal or written

So in conversation, זה הרגל ישן is completely normal. A learner will hear this kind of structure very often.