Getið þér sagt mér hvenær næsti gjalddagi er?

Yes. Getið þér means can you in a formal or polite style.

• getið = present tense of geta for þér
• þér = a formal you

So the opening literally works like Can you... ?

A less formal everyday version would usually be Geturðu... ?

Þér is the old formal way to address one person politely, similar to older European formal you systems.

So:

• þú = informal singular you
• þér = formal singular you

Because þér historically behaves like a plural form, the verb also appears in the plural form:

• Getur þú... ? = informal
• Getið þér... ? = formal

In modern Icelandic, þér can sound quite formal, stiff, or old-fashioned depending on the context. Many speakers today simply use þú even when being polite.

After geta in Icelandic, the next verb is normally in the supine form, not the infinitive.

So:

• geta sagt = can say / can tell
• not geta segja

This is something English speakers often notice because English uses the bare infinitive: can say. Icelandic does it differently.

Here:

• geta = can, be able to
• sagt = supine of segja (to say / to tell)

So Getið þér sagt mér... literally corresponds to Can you tell me...

mér is the dative form of ég and means to me.

The verb segja often takes the person being told in the dative:

• segja mér = tell me
• segja þér = tell you
• segja honum = tell him

So in this sentence:

• sagt mér = tell me

This is very normal Icelandic verb-and-case behavior, and it is something learners simply need to memorize with the verb.

Because hvenær næsti gjalddagi er is an indirect question: when the next due date is.

In Icelandic main clauses, the finite verb often comes early, but in subordinate clauses and indirect questions, the word order changes. The finite verb often comes later, after the subject and other elements.

Compare:

• Direct question: Hvenær er næsti gjalddagi? = When is the next due date?
• Indirect question: ... hvenær næsti gjalddagi er = ... when the next due date is

So the final er is completely normal here.

Because næsti gjalddagi is the subject of the clause hvenær næsti gjalddagi er.

That means it is in the nominative case.

• gjalddagi is a masculine noun
• singular nominative = gjalddagi
• the adjective must match it, so we get næsti

So:

• næsti gjalddagi = the next due date

The form næsti may look surprising if you expect an article, but words like næsti often make the phrase definite in meaning by themselves.

In Icelandic, you do not always need a separate definite article when a word like næsti already makes the noun phrase specific.

So:

• næsti gjalddagi naturally means the next due date
• not just a next due date

This is common with words such as next, same, last, and similar expressions in many languages.

Gjalddagi means due date, especially for a payment, bill, debt, or obligation.

It is often used in financial contexts.

Literally, it is built from ideas related to payment and day:

• gjald = payment / fee / charge
• dagi = day

So the literal sense is something like payment day or day when payment falls due.

Yes, it is grammatical and understandable, but it sounds fairly formal because of þér.

A more everyday version would be:

• Geturðu sagt mér hvenær næsti gjalddagi er?

That is what many speakers would probably say in ordinary conversation.

The original version might fit:

• formal customer service
• very polite written language
• old-fashioned polite speech

Yes, you could say:

• Getið þér sagt hvenær næsti gjalddagi er?

That would mean something like Can you say/tell when the next due date is?

But mér makes it more natural if you want the idea tell me specifically. In English, Can you tell me when... is also usually more natural than just Can you tell when...

So mér is not absolutely required for grammar, but it is very natural and useful here.

Yes. Hvenær means when.

It can be used in:

• direct questions: Hvenær kemur hann? = When is he coming?
• indirect questions: Ég veit ekki hvenær hann kemur. = I don’t know when he is coming.

In your sentence, it introduces the indirect question:

• hvenær næsti gjalddagi er = when the next due date is

A rough English-friendly guide would be:

• Getið þér ≈ GEH-tith thyehr
• sagt mér ≈ sahkt myehr
• hvenær ≈ KVEH-nighr
• næsti ≈ NYE-sti
• gjalddagi ≈ GYALT-ta-yi or GYAL-da-yi depending on speech
• er ≈ ehr

A few important sounds:

• þ is like th in thin
• ð is like th in this, though it can be softer depending on position
• æ sounds roughly like eye
• hv in modern Icelandic is usually pronounced like kv

If you want to sound natural, the biggest things to notice are the þ in þér, the hv in hvenær, and the æ in næsti.

A very literal breakdown is:

• Getið = can
• þér = you (formal)
• sagt = told / said
• mér = to me
• hvenær = when
• næsti gjalddagi = the next due date
• er = is

So the structure is roughly:

Can you tell me when the next due date is?

Or even more literally:

Can you tell me when next due-date is?

That last version is not natural English, but it helps show how the Icelandic sentence is built.