De virker stadig forelskede.

It can be either, because De is capitalized at the start of the sentence anyway.

• de = they
• De can also be the old-fashioned or formal you

So without more context, De virker stadig forelskede could mean either:

• They still seem in love
• You still seem in love (formal)

In modern everyday Danish, learners will most often meet de meaning they. The formal De exists, but it is much less common than it used to be.

Yes, virke can mean to work in some contexts, but it also very commonly means to seem or to appear.

Here it means seem:

• De virker trætte = They seem tired
• Hun virker glad = She seems happy

So in this sentence, virker does not mean that they are functioning or working. It means they give the impression of being in love.

Because the sentence is about appearance or impression, not a direct statement of fact.

• De er stadig forelskede = They are still in love
• De virker stadig forelskede = They still seem in love

So virker makes the statement a little less direct and a little more observational. The speaker is judging from what they see, not necessarily stating a known fact.

Because stadig is an adverb, and in this kind of sentence it naturally comes before the adjective or description.

Structure:

• De = subject
• virker = verb
• stadig = adverb
• forelskede = adjective/complement

So Danish places stadig in a very normal position here:

• De virker stadig forelskede
• Han virker stadig syg
• Hun er stadig glad

This is similar to English still, which also often comes before the final description: They still seem in love.

Because the adjective agrees with a plural subject, or with formal De.

Compare:

• Han er forelsket = He is in love
• Hun er forelsket = She is in love
• De er forelskede = They are in love

So:

• singular/common use: forelsket
• plural: forelskede

Since De here can be plural they, forelskede makes sense. The same plural form is also used with formal De.

Here it functions as an adjective.

The basic adjective is forelsket = in love. In this sentence it describes the subject after virker, just like an adjective does:

• De virker glade = They seem happy
• De virker forelskede = They seem in love

Historically, forms like this are related to participles, but for a learner it is most useful to think of forelsket / forelskede here as an adjective describing a person’s state.

Yes, absolutely. That is a very natural alternative.

Both can mean roughly the same thing:

• De virker stadig forelskede
• De ser stadig forelskede ud

A useful difference is:

• virker = seem, often a bit broader or more general
• ser ... ud = look, often more directly based on appearance

So:

• De virker stadig forelskede = they seem in love
• De ser stadig forelskede ud = they look in love

In many everyday situations, the difference is small.

Usually, de meaning they is written with a lowercase d.

So in the middle of a sentence you would normally write:

• Jeg tror, de stadig er forelskede.

The capitalized De is mainly used for formal you. But in your sentence, De is at the beginning, so capitalization does not help us decide the meaning.

That is why context matters here.

The exact pronunciation can vary a bit by speaker, but a learner should know a few practical points:

• the r in forelskede is not like a strong English r
• unstressed e endings are often weak, like a soft uh
• the word is said as one flowing unit, not syllable-by-syllable in a very careful way

You do not need to pronounce every written e strongly. In natural speech, Danish often reduces unstressed endings.

A good learner goal is to say it smoothly rather than trying to pronounce each letter very clearly in an English way.

Yes. Stadig often means still, but depending on context it can also mean continually, constantly, or all the time.

For example:

• Han taler stadig. = He is still talking / He keeps talking
• Det regner stadig. = It is still raining

In your sentence, the most natural meaning is simply still:

• De virker stadig forelskede = They still seem in love

The pattern is:

subject + verb + adverb + adjective

So:

• De = subject
• virker = verb
• stadig = adverb
• forelskede = adjective/complement

This is a very useful pattern in Danish:

• Hun virker meget træt = She seems very tired
• De er stadig vrede = They are still angry
• Han virker lidt nervøs = He seems a little nervous

So this sentence is structurally very normal and useful as a model.