Settu brauðið á skurðarbrettið áður en þú skerð það.

Settu is the singular imperative of setja (to put / place / set).

So in this sentence, settu means put! when speaking to one person.

A few useful related forms:

• að setja = to put
• ég set = I put / am putting
• þú setur = you put / are putting
• settu! = put! (to one person)
• setjið! = put! (to more than one person)

So the sentence is giving an instruction.

The ending -ið is the suffixed definite article, which is how Icelandic usually says the.

• brauð = bread
• brauðið = the bread

Icelandic normally attaches the to the end of the noun instead of putting a separate word in front of it.

Here brauðið is the direct object of settu, but for this noun the nominative and accusative singular forms are the same, so it still appears as brauðið.

Because á can take different cases depending on the meaning:

• accusative = movement onto something
• dative = location on something

In this sentence, the bread is being moved onto the cutting board, so Icelandic uses the accusative:

• á skurðarbrettið = onto the cutting board

If you were talking about the bread already being there, you would use the dative:

• Brauðið er á skurðarbrettinu. = The bread is on the cutting board.

This is one of the most important preposition patterns in Icelandic.

Yes, it is one word. Icelandic very often forms nouns as compounds.

• skurðarbretti = cutting board
• skurðarbrettið = the cutting board

The final -ið is again the definite article.

The noun is built from:

• skurðar- = a linking form related to cutting
• bretti = board

So literally it is something like cutting-board. Compound nouns like this are extremely common in Icelandic.

Áður en means before when it introduces a full clause.

Here it introduces:

• áður en þú skerð það = before you cut it

This is different from using just áður, which is more like earlier / before as an adverb.

So:

• áður = before, earlier
• áður en ... = before ...

You can think of en here as part of the fixed expression áður en.

Because Icelandic, like English, often uses the present tense for instructions and for actions that are still in the future relative to another action.

So:

• áður en þú skerð það literally looks like before you cut it
• but the meaning is naturally future relative to the command: first put it down, then cut it

This is completely normal. English does something similar:

• Wash your hands before you eat.

Even though the eating happens later, English still uses the present form eat, not will eat. Icelandic works similarly here.

Because the second part is a normal clause with a finite verb:

• þú skerð það = you cut it

In Icelandic, ordinary finite clauses normally need an expressed subject, so þú is included.

In the first part, the subject is not stated because it is an imperative:

• Settu ... = Put ...

Imperatives usually leave the subject unspoken, since it is automatically understood as you.

So the pattern is:

• command: subject omitted
• normal subordinate clause: subject stated

Það refers back to brauðið (the bread).

Since brauð is a neuter singular noun, the pronoun referring to it is also neuter singular:

• brauð = neuter
• það = it (neuter singular)

So:

• skerð það = cut it

This is a good example of Icelandic pronouns matching the gender and number of the noun they refer to.

Skerð is the 2nd person singular present form of skera (to cut).

Some useful forms:

• að skera = to cut
• ég sker = I cut / am cutting
• þú skerð = you cut / are cutting
• hann/hún/það sker = he/she/it cuts

So in the sentence:

• þú skerð það = you cut it

This is a common strong verb, so it does not behave exactly like all regular verbs.

Because this is a subordinate clause, and subordinate clauses in Icelandic do not follow the normal main-clause V2 pattern.

So you get:

• áður en þú skerð það

with the order:

1. conjunction phrase áður en
2. subject þú
3. verb skerð
4. object það

By contrast, main clauses in Icelandic often place the finite verb early because of V2 word order. But after áður en, the clause is subordinate, so the subject comes before the verb.

You would change the imperative settu to the plural imperative setjið.

So:

• Settu brauðið á skurðarbrettið áður en þú skerð það. = said to one person
• Setjið brauðið á skurðarbrettið áður en þið skerið það. = said to more than one person

Notice that both the imperative and the later verb change:

• þú skerð = you cut (singular)
• þið skerið = you cut (plural)

This is useful because Icelandic distinguishes singular and plural you.