Ég hef mikla vinnu í dag.

Hafa is the infinitive, meaning to have. In this sentence, the verb is conjugated for 1st person singular because the subject is ég (I).

So:

• ég hef = I have
• að hafa = to have

This is similar to English I have vs. to have.

The basic adjective is mikill, which often means big, great, or much/a lot of, depending on context.

In Ég hef mikla vinnu í dag, it means a lot of because it is describing vinnu (work) in the sense of workload.

So the phrase:

• mikla vinnu = a lot of work

It is not a separate word for lot. Icelandic often uses an adjective here where English uses a phrase like a lot of.

Because Icelandic adjectives must agree with the noun they describe in:

• gender
• number
• case

Here, vinnu is:

• feminine
• singular
• accusative

So the adjective mikill has to match that, and the correct form is mikla.

Very roughly:

• mikill = masculine nominative singular
• mikil = feminine nominative singular
• mikið = neuter nominative/accusative singular
• mikla = feminine accusative singular

That is why mikla vinnu is correct.

The dictionary form is vinna, but in this sentence it appears as vinnu because it is the direct object of hef.

After hafa (to have), the thing you have is usually in the accusative case.

So:

• nominative: vinna
• accusative: vinnu

That is why the sentence says Ég hef mikla vinnu.

Here it is a noun.

This can be confusing because vinna can also be a verb meaning to work or to win, depending on context.

In this sentence:

• vinnu = noun = work
• hef is the verb = have

So the structure is:

• Ég = I
• hef = have
• mikla vinnu = a lot of work
• í dag = today

Icelandic does not always use articles the same way English does.

In English, we say a lot of work, but in Icelandic the idea is expressed simply with:

• mikla vinnu

There is no separate word corresponding exactly to English a in this phrase.

That is very normal. Icelandic often expresses quantities more directly than English does.

Because the sentence is talking about work in general or workload, not a specific piece of work already identified as the work.

So:

• mikla vinnu = a lot of work
• not the work

This is similar to English, where work is often uncountable:

• I have a lot of work today
• not usually I have a lot of the work today, unless you mean a specific set of tasks

Í dag literally means in day or on this day, but as a fixed expression it simply means today.

It is one of the most common time expressions in Icelandic.

So:

• í dag = today

You should learn it as a set phrase.

Because the preposition í can take different cases, and in the fixed time expression í dag the noun appears in the accusative singular form.

The noun is:

• nominative: dagur
• accusative: dag

So:

• í dag = today

This is a common pattern in Icelandic prepositional expressions, and it is often easiest to memorize the whole phrase.

Yes. Icelandic word order is fairly flexible, but it follows important rules, especially the verb-second tendency in main clauses.

The neutral order here is:

• Ég hef mikla vinnu í dag.

But you can also say:

• Í dag hef ég mikla vinnu.

That version emphasizes today more.

What you usually cannot do in a normal main clause is move things around freely without keeping the finite verb in the right place.

So word order can change, but not randomly.

Yes. That is a very natural alternative.

• Ég hef mikla vinnu í dag = I have a lot of work today
• Ég er með mikla vinnu í dag = literally I am with a lot of work today, but naturally also I have a lot of work today

The version with hafa is straightforward and clear. The version with vera með is also common in everyday speech.

You add ekki (not):

• Ég hef ekki mikla vinnu í dag.

That means I do not have a lot of work today.

A stronger version might be:

• Ég hef enga vinnu í dag. = I have no work today

So:

• ekki mikla vinnu = not a lot of work
• enga vinnu = no work

Because vinna in this sentence refers to work in general / workload, not to a countable item like a job or a task.

So mikla vinnu works like English a lot of work, where work is also uncountable.

If you wanted to talk about countable tasks, you would usually use a different noun, such as verkefni (tasks / assignments / projects), depending on context.

So this sentence is about having a heavy workload, not about counting separate jobs.