يهتم صديقي بالعمل.

A careful MSA pronunciation is:

yahtammu ṣadīqī bil-ʿamali

With full vowel marks, it is:

يَهْتَمُّ صَدِيقِي بِالْعَمَلِ

A few pronunciation notes:

• يهتم = yahtammu
• صديقي = ṣadīqī
• بالعمل = bil-ʿamali
• The letter ع in العمل is the consonant ʿayn, which does not exist in English.
• The بِ + ال combination becomes بِال in writing, pronounced bil- here.

The sentence breaks down like this:

• يهتم = he is interested / he cares
• صديقي = my friend
• بالعمل = in work / about work / in the work, depending on context

Grammatically:

• يهتم is the verb
• صديقي is the subject
• بالعمل is a prepositional phrase attached to the verb

So the structure is:

verb + subject + prepositional phrase

Because Arabic very often uses verb-first word order in verbal sentences.

So:

• يهتم صديقي بالعمل = a normal verbal sentence
• literally: is interested my friend in work

This is completely natural in Arabic.

You can also say:

صديقي يهتم بالعمل

That is also correct, but it puts more focus on my friend. So both are possible, but the sentence you were given uses a very common Arabic pattern.

Because the ending ـي here is the possessive suffix meaning my.

So:

• صديق = friend
• صديقي = my friend

This is a very common Arabic pattern:

• كتابي = my book
• بيتي = my house
• أستاذي = my teacher

So in this sentence, صديقي is not just friend. It specifically means my friend.

يهتم is the imperfect form, which in MSA is used for present, ongoing, or habitual meaning depending on context.

Here it means something like:

• he is interested
• he cares
• he takes an interest

The dictionary form is اهتمّ بـ.

A few useful facts:

• root: ه م م
• past tense: اهتمّ
• present/imperfect: يهتمّ

Notice the doubled final consonant in pronunciation, shown by the shadda:

• يَهْتَمُّ

That final mm sound is important.

Because the verb اهتمّ normally takes the preposition بِـ.

So Arabic says:

اهتمّ بـ ...

This means to be interested in ... or to care about ...

That is just the normal pattern of the verb. English says interested in, while Arabic uses مهتمّ بـ or يهتمّ بـ.

So:

• يهتم بالعمل = he is interested in work
• not normally يهتم العمل

In other words, the بـ is required by the verb.

Because Arabic attaches many short prepositions directly to the following word.

Here:

• بِ = with / in / about, depending on context
• العمل = the work / work

Together they become:

بالعمل

This is extremely common in Arabic. The same thing happens with other short particles too.

For example:

• بالبيت = in the house
• بالمدرسة = at the school

So بالعمل is simply بِ + العمل written together.

It can mean either one, depending on context.

In Arabic, الـ does not always translate neatly as English the. Sometimes it can refer to something general or abstract.

So بالعمل may mean:

• in the work
• at work
• about work
• in work in a general sense

In many cases, Arabic uses الـ where English would just use a bare noun like work.

So you should not always translate العمل mechanically as the work. Context decides the most natural English meaning.

Because العمل comes after the preposition بِـ, and nouns after prepositions are normally in the genitive case in MSA.

So in full vowelled form:

• بِالْعَمَلِ

That final -i is the genitive ending.

This is a basic rule:

• after في
• after من
• after على
• after بِـ

the following noun is usually genitive.

So here:

• بالعملِ = genitive because it follows بِـ

Because the noun has an attached possessive suffix ـي meaning my.

In many cases like this, the usual case ending is not clearly visible in the simple written form.

So although صديقي is the subject of the sentence, you do not see a separate obvious nominative ending the way you might with other fully inflected nouns.

The important thing for a learner is:

• صديقي is the subject
• the ـي means my
• the word stays صديقي in this sentence

You can say:

صديقي يهتم بالعمل

This is also correct.

Compare:

• يهتم صديقي بالعمل = verb-first, very common verbal-sentence order
• صديقي يهتم بالعمل = subject-first, with more attention on my friend

The meaning is basically the same, but the sentence structure and emphasis are slightly different.

In MSA, a simple present-tense negation is:

لا يهتم صديقي بالعمل

This means:

My friend is not interested in work
or
My friend does not care about work

So you just add لا before the imperfect verb:

• يهتم = he is interested
• لا يهتم = he is not interested