Милый друг уже здесь.

In Russian, the verb to be is usually omitted in the present tense.

So:

• Милый друг уже здесь. = The dear friend is already here.
• literally: Dear friend already here.

This is completely normal Russian. In the past or future, forms of быть would appear:

• Милый друг был здесь. = The dear friend was here.
• Милый друг будет здесь. = The dear friend will be here.

Because милый is an adjective agreeing with друг.

Russian adjectives must agree with the noun in:

• gender
• number
• case

Here, друг is:

• masculine
• singular
• nominative

So the adjective also takes the masculine singular nominative form:

• милый друг

Compare:

• милая подруга = dear female friend
• милое письмо = dear/sweet letter
• милые друзья = dear friends

Yes, друг is masculine.

A very common clue in Russian is the noun ending:

• nouns ending in a hard consonant are often masculine
• друг ends in г, so it is masculine

That is why the adjective is милый, not милая or милое.

Also, друг means friend in the masculine form. A specifically feminine version is often:

• подруга = female friend

Милый can mean different things depending on context, such as:

• dear
• sweet
• nice
• lovely
• sometimes cute

With друг, it often has the sense of:

• dear friend
• beloved friend
• sweet friend

The exact tone depends on context. It can sound affectionate, warm, literary, or emotional.

Уже means already.

In this sentence it comes before здесь:

• Милый друг уже здесь.

This is a very natural placement. It emphasizes that the friend is here already now.

Russian word order is flexible, so you may also see:

• Милый друг здесь уже.
• Уже милый друг здесь. — possible, but much less neutral and more stylistically marked

The version you have is the most straightforward and natural for ordinary speech.

Both здесь and тут can mean here.

In many situations they are interchangeable:

• Он здесь.
• Он тут.

Very broadly:

• здесь can sound a bit more neutral or standard
• тут can sound a bit more conversational

So Милый друг уже здесь is a perfectly normal standard sentence. You might also hear:

• Милый друг уже тут.

That would still be natural, just slightly more colloquial in tone.

Russian has no articles like a or the, so the sentence itself does not specify that.

Depending on context, Милый друг уже здесь could be understood in English as:

• The dear friend is already here
• A dear friend is already here
• sometimes even My dear friend is already here, if the situation makes that clear

Russian often leaves this kind of information to context.

In this sentence, милый друг is most naturally the subject:

• Милый друг уже здесь. = The dear friend is already here.

If you were speaking to someone and calling them dear friend, Russian would usually show that with punctuation and intonation:

• Милый друг, уже здесь? = Dear friend, already here?
• Милый друг! = Dear friend!

So the lack of a comma here strongly suggests that милый друг is not direct address, but the person being talked about.

Yes. Russian word order is flexible, and changing it can shift the emphasis.

Neutral order:

• Милый друг уже здесь.

Other possible orders:

• Уже здесь милый друг. — more poetic or marked
• Здесь уже милый друг. — emphasizes here
• Милый друг здесь уже. — can sound slightly more emphatic or conversational

Even though several versions are possible, the original sentence is the most neutral and learner-friendly.

The words милый друг are in the nominative case, because they function as the subject of the sentence.

Breakdown:

• милый — masculine singular nominative adjective
• друг — masculine singular nominative noun

The adverbs do not change for case:

• уже = already
• здесь = here

So the only inflected part here is the noun phrase милый друг.

It is grammatically neutral, but the phrase милый друг can feel a bit affectionate or sometimes literary depending on context.

• In everyday speech, people often just say друг or use a name.
• милый друг may sound warm, emotional, old-fashioned, or poetic.
• In writing, songs, literature, or expressive speech, it fits very naturally.

So the sentence is correct and natural, but the phrase милый друг carries a noticeable tone, not just plain factual wording.