Advokaten läser ordern.

Because Swedish usually puts the definite article onto the noun itself as an ending.

So:

• advokat = lawyer
• advokaten = the lawyer
• order = order
• ordern = the order

This is one of the biggest differences from English. Instead of saying the lawyer, Swedish often says lawyer-the in effect.

A useful extra note: if there is an adjective, Swedish often uses both a separate article and the noun ending:

• den skickliga advokaten = the skilled lawyer

The base form is advokat.

• en advokat = a lawyer
• advokaten = the lawyer

So advokat is an en-word (common gender noun), and its definite singular form is made with -en.

The base form is order, and the definite form is ordern.

Some Swedish en-words do not take -en in the most obvious way. Nouns ending in certain unstressed patterns, including many words ending in -er, often just take -n in the definite singular.

So:

• en order = an order
• ordern = the order

This is something you largely learn word by word, but it is a normal Swedish pattern.

It is singular definite: the order.

That can be confusing for English speakers, because it does not look like English singular/plural patterns.

For this noun:

• en order = singular indefinite
• ordern = singular definite
• order = plural indefinite
• orderna = plural definite

So in this sentence, ordern means the order, not the orders.

läser is the present tense of the verb läsa.

• läsa = to read
• läser = reads / is reading

So:

• Advokaten läser ordern. = The lawyer reads the order / The lawyer is reading the order

As in English, the simple present can sometimes translate naturally as either a general present or an action happening now, depending on context.

No. In Swedish, verbs do not change according to the person or number of the subject in the present tense.

You say:

• jag läser = I read / am reading
• du läser = you read / are reading
• advokaten läser = the lawyer reads / is reading
• de läser = they read / are reading

So läser stays the same.

Yes. In this sentence, the order is:

• Advokaten = subject
• läser = verb
• ordern = object

So it follows the familiar Subject–Verb–Object pattern:

• The lawyer
  • reads
    • the order

A useful extra note: Swedish main clauses follow the V2 rule, which means the verb must be in the second position. In this simple sentence, that gives the same order as English. But if you move something else to the front, the subject comes after the verb:

• I dag läser advokaten ordern. = Today, the lawyer reads the order.

The ä in läser is pronounced roughly like the e in bed, but usually a bit longer.

So läser is approximately:

• LEH-ser

That is only an English-style approximation, but it is a good start.

Not if you mean the lawyer reads the order.

In Swedish, singular count nouns usually need marking for indefiniteness or definiteness:

• en advokat = a lawyer
• advokaten = the lawyer
• en order = an order
• ordern = the order

So:

• Advokaten läser ordern. = correct for The lawyer reads the order

A bare singular noun like advokat or order without an article or definite ending is usually not correct in a normal sentence like this.