Det här är en vanlig dag.

"Det här" literally means "this" (as in this thing / this situation).

In "Det här är en vanlig dag." it functions as the subject of the sentence, just like "This" in English:

• Det här = This
• är = is
• en vanlig dag = an ordinary/normal day

So the structure is directly parallel to English: This is an ordinary day.

Both can be translated as "this", but they’re used differently:

• det här is used with ett-words (neuter nouns) or as a standalone "this" (not directly attached to a noun).

  • det här huset = this house (hus is an ett-word)
  • Det här är en vanlig dag. = This is an ordinary day.

• den här is used with en-words (common gender nouns):

  • den här dagen = this day (dag is an en-word)
  • den här boken = this book

In your sentence, "det här" is not directly modifying a noun; it’s the standalone subject "this", so "det här" is correct.
If you explicitly mentioned the day, you’d say:

• Den här dagen är vanlig. = This day is ordinary.

Yes, you can, but the nuance changes slightly:

• Det här är en vanlig dag.

  • Very common in spoken Swedish.
  • Neutral and natural in everyday conversation.

• Detta är en vanlig dag.

  • Sounds more formal, written, or sometimes a bit old-fashioned or emphatic in speech.
  • More common in written texts, presentations, or formal style.

Both are grammatically correct and mean essentially the same thing: This is an ordinary day.

"är" is the present tense of "att vara" (to be).
Swedish is simpler than English here: the verb does not change with the subject.

• jag är = I am
• du är = you are
• han/hon/den/det är = he/she/it is
• vi är = we are
• ni är = you (plural) are
• de är = they are

So in "Det här är en vanlig dag.", "är" is just the standard present tense form, regardless of what the subject is. There is no separate am/is/are.

Swedish has two grammatical genders:

• en-words (common gender)
• ett-words (neuter gender)

Each indefinite singular noun takes en or ett:

• en dag (a day) → en-word
• ett hus (a house) → ett-word

You must memorize the gender when you learn a noun.
Since "dag" is an en-word, you say:

• en dag = a day
• en vanlig dag = an ordinary day

Using "ett dag" would be incorrect.

This is about indefinite vs. definite forms.

• en dag = a day (indefinite)
• dagen = the day (definite)

When you say "en vanlig dag", you are talking about any typical day, not a specific known day:

• en vanlig dag = a normal/ordinary day (in general)

If you want to talk about a specific day that you and the listener know, you use the definite form:

• den vanliga dagen = the ordinary day
• Den vanliga dagen är lång. = The ordinary day is long.

So "en vanlig dag" is correct here because the sentence describes a day in general, not the particular day.

Adjectives in Swedish do change form, but here "vanlig" is already in the correct basic form: common gender, singular, indefinite.

Basic pattern:

• en vanlig dag = a normal day
• ett vanligt hus = a normal house
• den vanliga dagen = the normal day
• de vanliga dagarna = the normal days

So:

• With an en-word, singular, indefinite → vanlig (no extra ending)
• With an ett-word, singular, indefinite → usually -t: vanligt
• With definite or plural → usually -a: vanliga

Since "dag" is an en-word, singular, indefinite, "vanlig" stays as "vanlig":
en vanlig dag.

Both can often be translated as "It is an ordinary day.", but the nuance differs:

• Det här är en vanlig dag.

  • More like "This is an ordinary day."
  • Points to this particular situation / day right now.
  • Slightly more specific or emphatic: this one, right here.

• Det är en vanlig dag.

  • More neutral "It is an ordinary day."
  • Can describe the day more generally, without special emphasis on this.

In many contexts both will be understood similarly, but "det här" feels more like actually pointing to the situation in front of you.

Grammatically it’s possible, but it sounds unusual and marked in normal speech.

• Det här är en vanlig dag.

  • Standard, neutral word order: Subject – Verb – Predicate

• En vanlig dag är det här.

  • Sounds poetic, dramatic, or stylistically special.
  • Similar to English: "An ordinary day, this is." (Yoda-style / poetic emphasis)

So for everyday Swedish, keep "Det här är en vanlig dag."

Approximate pronunciation (Swedish standard):

• Det – often pronounced like "de", with a very soft or almost silent t
• här – like "hair" in English but with a slightly more open vowel
• är – like "air", but shorter and more closed
• en – like a short "en" in "ten"
• vanlig – roughly "VAHN-lig", where:
  • a is long, like in "father"
  • n
    • l blend
  • g is soft; often sounds like "vanli"
• dag – roughly "daag":
  • long a (again like "father")
  • g is often very soft or almost silent in many accents

In IPA (simplified Central Swedish):
[deː hɛːr ɛr en ˈvɑːn.lɪg dɑːg]
(Exact sounds vary slightly by region.)