Bagasjelappen er blå.

Because Norwegian usually puts the definite article on the end of the noun.

• en bagasjelapp = a baggage tag
• bagasjelappen = the baggage tag

So the ending -en here means the.

In a simple noun phrase, Norwegian normally does not use a separate word for the the way English does. The definiteness is built into the noun itself.

So:

• bagasjelappen = the baggage tag

You do often get an extra definite word when there is an adjective before the noun:

• den blå bagasjelappen = the blue baggage tag

That is a very common Norwegian pattern called double definiteness.

The dictionary form is en bagasjelapp.

That means:

• en = the indefinite article for this noun
• bagasjelapp = baggage tag

Then the definite singular form becomes bagasjelappen.

Because Norwegian usually writes compound nouns as a single word.

Here, bagasjelapp is made from:

• bagasje = baggage
• lapp = tag / slip / label

So bagasjelapp is literally something like baggage-tag, and Norwegian writes that as one word, not two.

This is very important, because English speakers often want to separate compounds when writing Norwegian.

Er is the present tense of å være, which means to be.

So:

• er = is / am / are, depending on context

In this sentence it means is.

A useful point: Norwegian does not change the verb for different persons in the present tense:

• jeg er = I am
• du er = you are
• han er = he is
• vi er = we are

The form stays er.

Because the noun is singular and non-neuter, and the adjective is being used after er.

In Norwegian, adjectives can change form depending on gender and number. After er, the adjective still agrees with the noun.

Here are the basic patterns:

• bagasjelappen er blå = common gender singular
• huset er blått = neuter singular
• bagasjelappene er blå = plural

So blå is the correct form here because bagasjelappen is not a neuter singular noun.

Because this sentence is using blå as a predicate adjective after the verb er.

Compare:

• Bagasjelappen er blå. = The baggage tag is blue.
• Den blå bagasjelappen = The blue baggage tag.

So:

• after er: blå
• before the noun: den blå bagasjelappen

Both are correct, but they are different sentence structures.

Yes, in this sentence it is very similar to English:

• Bagasjelappen = subject
• er = verb
• blå = subject complement / adjective

So the pattern is:

subject + verb + adjective

That said, Norwegian main clauses follow the verb-second rule, so if another element comes first, the verb still stays in second position:

• I dag er bagasjelappen blå. = Today the baggage tag is blue.

A rough pronunciation guide is:

bah-GAH-sheh-lahp-pen er blaw

A few useful sound notes:

• sj in bagasje sounds like English sh
• pp in lappen is pronounced as a short consonant sound, not like two separate p sounds
• å in blå is a long vowel, somewhat like the vowel in law

The exact pronunciation of er can vary by dialect.

Yes, grammatically you can, but it changes the meaning.

• Bagasjelappen er blå. = The baggage tag is blue.
• En bagasjelapp er blå. = A baggage tag is blue.

The second sentence sounds less specific. It refers to an unspecified baggage tag, while bagasjelappen refers to a specific one already known from the context.