כולם כבר יושבים סביב השולחן.

In Hebrew, the verb to be is usually not expressed in the present tense.

So instead of saying Everyone already are sitting around the table, Hebrew simply says:

כולם כבר יושבים סביב השולחן

Literally, that is closer to:

Everyone already sitting around the table

The idea of are is understood automatically.

By contrast, in the past or future, Hebrew does use forms of to be when needed.

כולם means everyone, everybody, or all of them, depending on context.

It comes from כול / כל meaning all, with a plural ending that gives the sense of all of them.

In everyday Hebrew, כולם is extremely common and often works like English everyone.

Examples:

• כולם באו = Everyone came
• כולם יודעים = Everybody knows
• כולם כבר יושבים = Everyone is already sitting

Even though English everyone looks singular, Hebrew כולם behaves grammatically like a plural word, so the verb or participle after it is plural too.

Because כולם is grammatically plural.

יושבים is the masculine plural present-tense form of the verb לשבת (to sit).

So the agreement is:

• כולם ... יושבים = everyone ... sitting / all of them ... are sitting

If the group were specifically all female, you would normally say:

• כולן כבר יושבות סביב השולחן

So:

• יושבים = masculine plural
• יושבות = feminine plural

As in many places in Hebrew, the masculine plural can also be used for a mixed group.

In this sentence, it functions as the present-tense form of the verb לשבת (to sit).

Hebrew present tense is historically built from forms that also behave a lot like adjectives/participles, which is why they change for gender and number:

• יושב = masculine singular
• יושבת = feminine singular
• יושבים = masculine plural
• יושבות = feminine plural

So in practical learning terms, you can think of יושבים here as are sitting.

כבר means already.

It gives the idea that the action or situation has happened earlier than expected, or that by this point it is already the case.

So:

• כולם יושבים סביב השולחן = Everyone is sitting around the table
• כולם כבר יושבים סביב השולחן = Everyone is already sitting around the table

It often appears before the main verb or participle, just like here.

This is a very natural Hebrew word order:

• כולם = subject
• כבר = adverb
• יושבים = present-tense verb form

So the sentence flows as: Everyone already sitting around the table

Hebrew word order is fairly flexible, but this version sounds neutral and natural.

Other orders are possible for emphasis, for example:

• כבר כולם יושבים סביב השולחן = more like By now, everyone is sitting around the table
• כולם יושבים כבר סביב השולחן = possible, but less neutral in many contexts

So the given order is a standard, good one to learn.

סביב means around.

In this sentence, it introduces the place where people are sitting:

• סביב השולחן = around the table

It is a common preposition in Hebrew.

A very common alternative is:

• מסביב לשולחן

That also means around the table, and in many everyday situations it may sound a bit more colloquial or more explicit.

So both are useful:

• סביב השולחן
• מסביב לשולחן

Because the sentence refers to the table, not just a table.

The ה־ at the beginning is the Hebrew definite article, equivalent to English the.

So:

• שולחן = a table / table
• השולחן = the table

The phrase סביב השולחן therefore means around the table.

In pronunciation, ה attaches directly to the noun:

• השולחן = ha-shulchan

A common pronunciation is:

Kulam kvar yoshvim sviv ha-shulchan.

A rough guide:

• כולם = koo-LAM
• כבר = kvar
• יושבים = yosh-VEEM
• סביב = sveev or sviv
• השולחן = ha-shool-KHAN
  (with kh like the sound in German Bach or Hebrew ח)

Pronunciation varies a little by speaker and accent, but that will be understood clearly.

It can express both ideas, depending on context.

In English, we might say:

• They are sitting
• They are seated

Hebrew יושבים can cover both.

So כולם כבר יושבים סביב השולחן can suggest:

• they have taken their seats
• they are now in a seated position
• the meal/meeting may be about to begin

The exact nuance comes from context.

Yes. Hebrew normally uses the masculine plural for:

• an all-male group
• a mixed group
• a group of unknown gender composition

So כולם כבר יושבים is perfectly normal for everyone in a mixed group.

If you know the group is entirely female, you would usually say:

• כולן כבר יושבות סביב השולחן

So:

• כולם ... יושבים = mixed or masculine group
• כולן ... יושבות = all-female group

Yes. The difference depends on context, not on the word itself.

For example:

• כולם כבר יושבים סביב השולחן could be understood as
  Everyone is already sitting around the table
  or
  All of them are already sitting around the table

In many cases, those translations are basically the same in English.

So when you see כולם, think of a plural meaning like:

• everyone
• everybody
• all of them

and let the context decide which sounds most natural in English.

Yes: in Hebrew, לשבת literally means to sit, but it is also often used where English might say to be seated or even to stay / remain sitting depending on context.

In this sentence, it most naturally means:

• to be sitting
• to be seated

So יושבים is not unusual here at all. It is exactly the form Hebrew speakers would normally use.

Related forms:

• אני יושב / יושבת = I am sitting
• הוא יושב = he is sitting
• הם יושבים = they are sitting

So this sentence is a very good example of ordinary present-tense Hebrew.