Við tölum við lögfræðinginn.

Because they are two different words that just happen to be spelled the same.

• Við at the beginning = we
• við after tölum = a preposition meaning to or with

So the sentence structure is:

• Við = subject
• tölum = verb
• við lögfræðinginn = prepositional phrase, to/with the lawyer

This is very common in Icelandic: the same written form can have different meanings depending on its job in the sentence.

Because tölum is the 1st person plural present tense form of the verb tala.

• Dictionary form: tala = to talk / to speak
• við tölum = we talk / we speak

The ending -um marks we.
Also, the vowel changes from a to ö. This is a common Icelandic pattern called u-umlaut:

• tala
• við tölum

So tölum is not irregular in a random way; it follows a real sound-change pattern found in many Icelandic words.

It can mean all of those, depending on context.

Icelandic present tense often covers both:

• We speak with the lawyer
• We talk with the lawyer
• We are talking to the lawyer

Unlike English, Icelandic does not always need a separate progressive form like are talking. The simple present often does that job.

Yes, very much so.

tala við einhvern means to talk to someone / speak with someone.

So in this sentence, við belongs closely with the verb:

• tala við = talk to / with

This is a good expression to learn as a chunk, not just as a verb plus a random preposition.

It can be translated either way in English.

With tala, Icelandic við often corresponds to:

• talk to
• talk with
• speak to
• speak with

Which English version sounds best depends on context and style. In many cases, both are fine.

Because the noun is not in its dictionary form here.

The dictionary form is:

• lögfræðingur = lawyer

But after the preposition við in this meaning, the noun goes into the accusative case. So:

• nominative: lögfræðingur
• accusative: lögfræðing

Then Icelandic adds the definite article the to the end of the noun:

• lögfræðinginn = the lawyer (accusative singular)

So the full change is:

• lögfræðingur → lögfræðing → lögfræðinginn

It is the definite article, meaning the.

In Icelandic, the is usually attached to the end of the noun instead of being a separate word.

So:

• lögfræðingur = a lawyer / lawyer
• lögfræðinginn = the lawyer (in this case form)

One important detail: the exact shape of the ending changes with case, gender, and number. So you should not think of -inn as a single universal ending for the in every situation. It is just the form that fits this noun in this sentence.

Here, við takes the accusative.

That is why the noun is lögfræðinginn, not nominative lögfræðingurinn.

This is an important part of Icelandic grammar: many prepositions regularly require a certain case. So when learning a preposition, it is helpful to learn it together with the case it governs.

For this sentence:

• við
  • accusative

Yes, but the version you have is the most basic and neutral one:

• Við tölum við lögfræðinginn.

Icelandic does allow different word orders, but it follows a strong verb-second pattern in main clauses. That means if something else comes first, the verb usually still stays in the second position.

For example:

• Núna tölum við við lögfræðinginn. = Now we are talking to the lawyer.

Notice that when Núna moves to the front, tölum still comes second, and við the subject comes after it.

So the original sentence is standard, but Icelandic word order is somewhat flexible as long as those grammar rules are respected.