Learn Hardcore Swedish: Läkaren förklarar tydligt vad oro är. - The doctor explains clearly what anxiety is.

In this sentence, you are talking about a specific doctor (someone already known in the context), so Swedish uses the definite form läkaren. The base form läkare on its own is either “a doctor” (when you add en) or just the bare noun used in dictionaries and titles (e.g. att vara läkare – to be a doctor).

Can I use doktor instead of läkare here?

You can, but it changes the style and nuance a bit.

läkare = medical doctor (neutral, standard word in both speech and writing)
doktor = (1) academic title (PhD, MD), or (2) in everyday talk, especially with children, “the doctor”

So:

Läkaren förklarar tydligt vad oro är. – neutral, standard Swedish.
Doktorn förklarar tydligt vad oro är. – sounds more colloquial / old‑fashioned, like “the doc explains clearly what worry is.”

In most written or formal contexts about healthcare, läkare is preferred.

What does tydligt mean, and why does it come after förklarar?

tydligt means clearly. It is the adverb form of the adjective tydlig (clear).

In a main clause, Swedish normally has this word order:

Subject
Finite verb
Adverb
Rest of the sentence

So:

Läkaren (subject)
förklarar (finite verb)
tydligt (adverb)
vad oro är (the rest / object clause)

That is why tydligt comes right after förklarar.

Why is it vad oro är and not vad är oro, like in English “what is worry”?

Because this is an indirect question (a subordinate clause), not a direct question.

Direct question: Vad är oro? – What is worry?
Indirect question: Läkaren förklarar vad oro är. – The doctor explains what worry is.

In Swedish indirect questions and other subordinate clauses, you do not invert the subject and the verb the way you do in direct questions. The word order inside the subordinate clause is like in a statement:

oro är … (worry is …), introduced by vad
So: vad oro är, not vad är oro

Läkaren förklarar vad är oro is ungrammatical in Swedish.

What exactly does oro mean? Is it worry or anxiety?

oro is a general word for a feeling of worry, concern or unease. It overlaps with both worry and anxiety, depending on context.

Mild to moderate worry: Jag känner oro inför provet. – I feel worry / I’m worried about the exam.
General societal concern: Det finns stor oro i landet. – There is great concern in the country.

Compared to similar words:

oro – worry, concern, unease (neutral, covers a wide range)
ångest – strong anxiety, often intense and distressing
bekymmer (usually plural) – worries/problems (concrete concerns)

So oro is a good neutral choice for talking about the general feeling of being worried.

Why is there no article before oro? Why not vad en oro är or vad oron är?

Because oro here is an abstract, uncountable noun used in a general sense. In Swedish, such nouns usually appear without an article when you are talking about them in general:

vad oro är – what worry/anxiety is (in general)
vad frihet är – what freedom is
vad kärlek är – what love is

You add an article (or definite ending) when you mean a specific worry:

oron = the (specific) worry/concern
- Oron för framtiden är stor. – The worry about the future is great.

In your sentence, the doctor is explaining the concept of worry, so the bare form oro is used.

Why does är appear at the very end of vad oro är? Does Swedish put the verb last?

Swedish does not generally put the verb at the very end like German. The pattern in this kind of clause is:

question word
- subject
  - verb
    - (rest)

Here:

vad – question word (what)
oro – subject (worry)
är – verb (is)

There happens to be nothing after är, so the verb ends up last, but that’s not a rule in itself. You could continue the clause:

…vad oro egentligen är. – what worry really is.

Then är is no longer the last word. The key rule is: in this subordinate clause, the verb comes after the subject (no inversion).

Can I move tydligt somewhere else, like Läkaren tydligt förklarar vad oro är or Läkaren förklarar vad oro är tydligt?

You have to be careful with adverb placement because of the verb‑second rule.

Läkaren tydligt förklarar vad oro är – sounds wrong in standard Swedish.
- In a main clause, the finite verb (förklarar) must be in second position.
- Here you would get: Läkaren (1st), tydligt (2nd), förklarar (3rd), which breaks the rule.
Läkaren förklarar vad oro är tydligt – grammatically possible but feels awkward and unclear. It tends to sound like you are commenting on the whole preceding clause afterwards.

Natural alternatives:

Läkaren förklarar tydligt vad oro är. – most neutral.
Tydligt förklarar läkaren vad oro är. – puts emphasis on clearly.
Läkaren förklarar väldigt tydligt vad oro är. – with extra emphasis (väldigt tydligt = very clearly).
Läkaren förklarar vad oro är på ett tydligt sätt. – “in a clear way”.

Why is förklarar in the present tense? Could it also be past?

Swedish present tense (förklarar) is used for:

something happening right now: The doctor is explaining…
general, repeated or typical actions: The doctor explains… (whenever needed)

Swedish does not have a separate -ing form like English (is explaining), so Läkaren förklarar can cover both “explains” and “is explaining”, depending on context.

If you want the past, you simply use the preterite:

Läkaren förklarade tydligt vad oro är. – The doctor clearly explained what worry is.

If I put it in the past tense, should it be vad oro är or vad oro var?

Both are possible, but they mean slightly different things.

Läkaren förklarade tydligt vad oro är.
- The explaining happened in the past,
- but oro is a timeless concept that is still true now.
- Very natural when you are talking about definitions or facts.
Läkaren förklarade tydligt vad oro var.
- Suggests you are talking about how worry was in some past situation or under certain conditions,
- or in a story where everything is set firmly in the past.

In most cases where the doctor is explaining the definition of worry, Swedish speakers will keep är in the present even after a past‑tense main verb.

How do you pronounce the tricky words läkaren, förklarar, tydligt, and oro?

Approximate pronunciations (Swedish is stress‑timed; stressed syllable in CAPS):

läkaren – LÄ‑ka‑ren
- ä like in cat but a bit longer: [ɛː]
- [ˈlɛːkaɾɛn]
förklarar – för‑KLAR‑ar
- ö like British her (but a bit more rounded): [ø] / [œ]
- stressed on -klar-: [fœɾˈklɑːrar] (r often tapped or light)
tydligt – TYD‑ligt
- y is a fronted vowel, between ee and ü; like French u in lune: [yː]
- final -t is pronounced: [ˈtyːdlɪkt]
oro – O‑ro
- both o’s are long/rounded “oo” sounds (first one long): [ˈuːruː]

Listening to native audio (e.g. on Forvo or a good dictionary) and repeating out loud will help you master these vowel sounds.