اتصل بي.

Yes. اتصل بي is an imperative sentence, so it is giving a command or instruction.

In this sentence, اتصل means call/contact! addressed to you.

Arabic imperatives usually do not need a separate word for you. The subject is already built into the verb form.

By itself, اتصل is addressed to one male in Modern Standard Arabic.

So اتصل بي is specifically:

• Call/contact me — said to one man or boy

Related forms:

• اتصلي بي — said to one woman or girl
• اتصلا بي — said to two people
• اتصلوا بي — said to a group of males or a mixed group
• اتصلن بي — said to a group of females in very formal/classical usage

Because this verb normally uses the preposition بـ with the person contacted.

So Arabic says, literally, something like:

• contact/call + by/with + me

That is why you get:

• بـ + ي = بي

So:

• اتصل بي = contact me / call me

A direct-object form like اتصلني is not the normal standard pattern for this verb.

بي consists of:

• بـ = a preposition
• ـي = me / my suffix pronoun

Together:

• بي = with me / by me / me, depending on the verb and context

With اتصل, it means me in the sense of get in touch with me.

With vowels, it is:

• اِتَّصِلْ بِي

A common transliteration is:

• ittaṣil bī

A few pronunciation notes:

• the تّ has a shadda, so it is pronounced like a doubled t
• ص is an emphatic s
• بي is pronounced bī, with a long ee sound

The root is:

• و ص ل

This root has meanings connected to reaching, joining, connecting.

A related basic verb is:

• وصل = to arrive, reach, connect

From that same root, اتصل developed the meaning to make contact, get in touch, call.

It is from Form VIII.

Its past tense form is:

• اتصل = he contacted / got in touch

Its present tense is:

• يتصل = he contacts / gets in touch

Its imperative is:

• اتصل = contact! / call!

Knowing the form helps because many Arabic verbs follow predictable patterns across past, present, verbal noun, and imperative.

Because normal Arabic writing usually leaves out most short vowels.

So learners often see:

• اتصل بي

But the fully vowelled version is:

• اِتَّصِلْ بِي

This is very common in Arabic. Native readers usually know the correct pronunciation from context and familiarity with the word pattern.

It can mean either, depending on context.

In many situations, especially modern usage, اتصل بي is naturally understood as:

• Call me
• Get in touch with me
• Contact me

If the context is specifically about a phone call, call me is a very natural translation.

Yes. اتصل بي is perfectly good Modern Standard Arabic.

It is suitable for:

• formal writing
• instructions
• messages
• general standard usage

It is also easy for Arabic speakers to understand across the Arab world, even though everyday spoken dialects may pronounce or phrase it a little differently.

Because in Arabic, the verb itself already shows the subject.

In اتصل, the form already tells you that the speaker is addressing you.

So adding a separate pronoun such as أنت is usually unnecessary. You would only add it for emphasis or contrast, and even then it would often sound marked in a simple command.

At the beginning of the sentence, yes.

So when the sentence starts with اتصل, you pronounce the initial vowel:

• اِتَّصِلْ

This initial ا is part of what learners often meet as hamzat al-waṣl behavior. In simple terms:

• at the beginning, you pronounce it
• after certain preceding words, it may not be pronounced separately

For this sentence on its own, just pronounce it as ittaṣil.