صديقي يدعو صديقتي.

The ending -ي is the attached pronoun meaning my.

So:

• صديقي = my male friend
• صديقتي = my female friend

In Arabic, this kind of attached pronoun is very common. Instead of using a separate word for my, Arabic usually adds it directly to the noun.

Arabic marks grammatical gender much more clearly than English.

• صديق is male friend
• صديقة is female friend

After adding -ي for my, they become:

• صديقي = my male friend
• صديقتي = my female friend

So the sentence specifically has a male friend as the subject and a female friend as the object.

This happens because of ة at the end of صديقة. That letter is called tāʾ marbūṭa.

When the word stands by itself, it is usually pronounced like -a or -ah:

• صديقة = ṣadīqah / ṣadīqa

But when you add a suffix such as -ي meaning my, the ة is pronounced as t:

• صديقتي = ṣadīqatī

So this is a normal rule, not an irregular spelling.

يدعو is the present/imperfect form of the verb دعا.

Depending on context, يدعو can mean:

• he invites
• he calls
• he summons
• sometimes he calls upon or prays to

In this sentence, the intended meaning is determined by context and by the translation already shown to the learner. Grammatically, the verb form itself can cover several related meanings.

Because the subject is صديقي, which is masculine singular.

Arabic verbs agree with the subject, not the object. So even though صديقتي is feminine, that does not make the verb feminine. The person doing the action is my male friend, so the verb is he invites / he calls.

In this sentence, the order makes it clear:

• صديقي = the subject, the one doing the action
• يدعو = the verb
• صديقتي = the object, the one receiving the action

So the pattern here is subject + verb + object.

That is why the sentence means that my male friend is calling or inviting my female friend, not the other way around.

Because Arabic verbs already contain that information.

يدعو by itself already tells you:

• third person
• masculine
• singular

So it already means he invites / he calls. Arabic often leaves out subject pronouns unless they are needed for emphasis or contrast.

Because the suffix -ي already makes the noun definite.

Compare:

• صديق = a friend or just friend
• صديقي = my friend

Once a noun has a possessive suffix like my, it is already specific and definite, so ال is not used.

Arabic allows both patterns:

• صديقي يدعو صديقتي = my friend invites my friend
• يدعو صديقي صديقتي = same basic meaning

The sentence you were given uses subject first, which is also very common. A verb-first order is also common in Modern Standard Arabic. So this sentence is perfectly normal; it is just one of the possible word orders Arabic uses.

A common pronunciation is:

ṣadīqī yadʿū ṣadīqatī

A few helpful notes:

• ص is an emphatic s
• ع in يدعو is a throat sound that does not exist in English
• the final و in يدعو gives a long ū
• in صديقتي, the ت is pronounced because a suffix follows the ة

That is normal in everyday Arabic writing. Short vowels are usually omitted.

So learners normally see:

• صديقي يدعو صديقتي

Instead of a more fully vowelled version such as:

• صَدِيقِي يَدْعُو صَدِيقَتِي

Also, with the -ي suffix meaning my, the case ending is not clearly shown at the end in the usual spelling. So you often understand the grammar from word order and context rather than from visible endings.

Sometimes context in modern usage can give them a romantic meaning, but by themselves they normally mean male friend and female friend.

So for a learner, the safe default is:

• صديق = male friend
• صديقة = female friend

If a romantic meaning is intended, the surrounding context usually makes that clear.