المحامي هنا اليوم.

Because Arabic often uses nominal sentences in the present tense, and in those sentences there is usually no separate verb meaning is/am/are.

So:

• المحامي هنا اليوم = The lawyer is here today

Literally, it is more like:

• the-lawyer here today

Arabic understands the idea of is from the structure itself.

If you wanted a past or future meaning, then Arabic would normally use a verb, for example:

• كان المحامي هنا اليوم = The lawyer was here today
• سيكون المحامي هنا اليوم = The lawyer will be here today

محامي means lawyer.

The ال at the beginning is the Arabic definite article, meaning the.

So:

• محامي = a lawyer / lawyer
• المحامي = the lawyer

In this sentence, the noun is definite, so the meaning is the lawyer, not just a lawyer.

It is pronounced approximately:

• al-mu-ḥaa-mii

A more careful breakdown:

• ال = al
• محا = muḥā
• مي = mī

Notes:

• ḥ represents the Arabic letter ح, a stronger, breathier sound than normal English h
• ā is a long a
• ī is a long ee sound

So the whole word is roughly al-mu-ḥaa-mii.

That -ي is part of the word itself. The singular noun محامي is the normal form for lawyer.

It is related to a common Arabic pattern used for professions or people associated with something. You do not need to think of the ي here as meaning my.

So:

• محامي here does not mean my lawyer
• المحامي simply means the lawyer

If you wanted my lawyer, that would usually be:

• محاميَّ or, in ordinary unvoweled writing, also محامي depending on context

So context and vowels matter.

هنا means here.

It is an adverb of place, telling you where the lawyer is.

So the sentence breaks down as:

• المحامي = the lawyer
• هنا = here
• اليوم = today

Together: The lawyer is here today.

No. They look a little similar to beginners, but they mean different things.

• هنا = here
• هذا = this (masculine)

Examples:

• المحامي هنا = The lawyer is here
• هذا المحامي = This lawyer

So in your sentence, هنا is about location, not this.

اليوم means today.

It is an adverb of time, telling you when the lawyer is here.

So:

• هنا answers where?
• اليوم answers when?

That is why both can appear in the same sentence:

• المحامي هنا اليوم = The lawyer is here today

Yes, Arabic can often change word order for emphasis, but المحامي هنا اليوم is a very natural neutral order.

This sentence starts with the topic:

• المحامي = the lawyer

Then it gives information about him:

• هنا = here
• اليوم = today

Other orders can be possible, depending on emphasis, for example:

• هنا المحامي اليوم = The lawyer is here today / The lawyer is here today, right here
• اليوم المحامي هنا = Today, the lawyer is here

But for a learner, المحامي هنا اليوم is an excellent standard pattern.

Yes. It is a complete Arabic sentence.

In Arabic grammar, this is a nominal sentence:

• المحامي = the subject/topic (مبتدأ)
• هنا اليوم = the predicate/comment (خبر plus time expression)

Even though there is no written is, the sentence is complete and natural.

In fully vocalized formal Arabic, yes, case endings can appear.

A fully marked version would commonly be:

• المحاميُ هنا اليومَ

Why?

• المحاميُ is the subject of the nominal sentence, so it is nominative
• اليومَ is functioning adverbially (today), so it is commonly accusative
• هنا is an indeclinable adverb, so it does not change like a regular noun

However, in normal Arabic writing, short vowels and case endings are usually not written, so you normally see:

• المحامي هنا اليوم

Because هنا is not a regular noun like lawyer or day. It is an adverb meaning here, and words like this do not normally take the definite article ال.

Compare:

• المحامي = the lawyer
• اليوم = today / the day
• هنا = here

So there is nothing missing. هنا is already the correct form.

Yes, literally اليوم is related to the day.

But in actual usage, اليوم very often means today.

So in this sentence:

• المحامي هنا اليوم

the natural meaning is:

• The lawyer is here today

not:

• The lawyer is here the day

This is a normal idiomatic use of اليوم.

Not as written.

Because the noun has ال, the sentence specifically says:

• المحامي = the lawyer

If you wanted a lawyer is here today, you would use the indefinite form:

• محامٍ هنا اليوم

So the difference is:

• المحامي هنا اليوم = The lawyer is here today
• محامٍ هنا اليوم = A lawyer is here today

Yes, محامي is masculine in this sentence.

A common feminine form is:

• المحامية

So:

• المحامي هنا اليوم = The male lawyer is here today
• المحامية هنا اليوم = The female lawyer is here today

The rest of the sentence stays the same.

No. You would not normally say في هنا in standard Arabic.

هنا already means here, so adding في before it is usually not correct in this basic use.

Say:

• المحامي هنا اليوم = The lawyer is here today

If you want a more specific place, you can use a prepositional phrase such as:

• المحامي في المكتب اليوم = The lawyer is in the office today

So:

• هنا works by itself
• في is used before a noun like المكتب

This sentence works perfectly well in Modern Standard Arabic, and it is also understandable in many spoken varieties.

That said, spoken dialects may pronounce things differently or use slightly different word choices. But as a piece of MSA, المحامي هنا اليوم is fully natural and correct.