Learn Hardcore Danish: Nogle af mine søskende har et alvorligt problem med at komme til tiden. - Some of my siblings have a serious problem with arriving on time.

nogle is normally used with countable plural nouns:
- nogle bøger = some books
- nogle af mine venner = some of my friends
nogen is more often used:
- in questions and negatives:
  - Har du nogen søskende? = Do you have any siblings?
  - Jeg har ikke nogen penge. = I don’t have any money.
- with singular nouns in some contexts.

Here, søskende is a plural countable noun, and the sentence is a positive statement, so nogle is the natural choice: Nogle af mine søskende … = Some of my siblings …

Why do we say af mine søskende? Can’t we just say nogle mine søskende?

The preposition af is needed to express “some of my …” in Danish.

nogle søskende = some siblings (in general, not specified as yours)
nogle af mine søskende = some of my siblings (a subset of your siblings)

Danish regularly uses nogle af + possessive + noun to mean some of my/your/their …:

nogle af mine venner = some of my friends
nogle af hendes bøger = some of her books

Why is it mine søskende and not min søskende?

The possessive pronoun agrees in number with the noun:

min = my (with singular nouns of common gender):
- min bog (one book)
mit = my (with singular nouns of neuter gender):
- mit hus (one house)
mine = my (with plural nouns, all genders):
- mine bøger (my books)
- mine huse (my houses)

Søskende is plural here (siblings), so you must use mine:
mine søskende = my siblings.

Is søskende singular or plural? How do you say “a sibling”?

Søskende is usually treated as a plural collective noun meaning siblings.

Jeg har tre søskende. = I have three siblings.
Har du søskende? = Do you have siblings?

If you want to talk about one specific sibling, you normally say:

en søster = a sister
en bror = a brother

There is a form en søskende in very formal/technical language (e.g. in questionnaires), but in everyday speech people almost always say en bror or en søster instead.

Why is it et alvorligt problem and not en alvorlig problem?

Danish nouns have grammatical gender:

en-words (common gender)
et-words (neuter)

The word problem is an et-word:

et problem, to problemer

The adjective must agree in form with the noun:

alvorlig
- en-word singular: en alvorlig sag
alvorligt
- et-word singular: et alvorligt problem
alvorlige
- plural: alvorlige problemer

So here: et (neuter) problem → alvorligt is the correct form:
et alvorligt problem = a serious problem.

Why is the adjective alvorligt and not alvorlig in this sentence?

Because alvorligt is the neuter singular form of the adjective, matching et problem.

Patterns:

Common gender singular (en-word):
- en alvorlig fejl = a serious mistake
Neuter singular (et-word):
- et alvorligt problem = a serious problem
Plural (all genders):
- alvorlige problemer = serious problems

So alvorligt is required by the neuter noun problem.

What does the structure har et alvorligt problem med at + infinitive mean exactly?

The structure:

har et alvorligt problem med at + [verb]

means roughly “have a serious problem with [verb]-ing” in English.

Examples:

Han har et problem med at sove.
= He has a problem with sleeping / He has trouble sleeping.
De har et alvorligt problem med at betale regningerne.
= They have a serious problem with paying the bills.

In your sentence:

har et alvorligt problem med at komme til tiden
= have a serious problem with being on time / with getting there on time.

Why do we use med at komme? Could we say just problem at komme?

You need the preposition med here. The normal Danish pattern is:

problem med at + infinitive

So:

problem med at komme = problem with coming
problem med at forstå = problem with understanding
problem med at finde vej = problem with finding the way

Saying problem at komme without med is not idiomatic Danish in this meaning. Keep the pattern problem med at + verb.

What does komme til tiden mean, and how is it different from komme i tide?

Both relate to being on time, but with a nuance:

komme til tiden
= arrive at the agreed/official time, not late
(e.g. for work, class, an appointment)
komme i tide
= arrive in time, i.e. early enough so that something can still happen or be prevented
(like English “in time” vs “on time”)

Examples:

Hun kommer aldrig til tiden.
= She never arrives on time (for scheduled things).
Heldigvis kom vi i tide til at redde hunden.
= Fortunately, we arrived in time to save the dog.

In your sentence, komme til tiden is about punctuality for regular, fixed-time events.

Why is it til tiden and not i tiden?

The fixed expression is:

komme til tiden = be/come on time

The preposition til is the one used in this idiom. I tiden would literally mean “in the time” and does not carry the punctuality meaning.

So you memorise:

til tiden in this phrase:
- at komme til tiden = to arrive on time
- at være der til tiden = to be there on time

Can I change the word order, for example … har et alvorligt problem at komme til tiden med?

No, that word order would be ungrammatical in standard Danish.

The natural order here is:

har et alvorligt problem med at komme til tiden

You should keep:

har (verb)
et alvorligt problem (object)
med (preposition)
at komme til tiden (infinitive clause)

The preposition med must stay directly before at + verb in this construction.

Is there any difference between søskende and saying brødre og søstre?

Yes, in nuance:

søskende = siblings (gender-neutral, collective)
brødre og søstre = brothers and sisters (explicitly mentions both)

Often they overlap:

Har du søskende? = Do you have siblings?
Har du brødre og søstre? = Do you have brothers and sisters?

In many contexts they mean effectively the same, but søskende is simpler and more common when you just mean “siblings” in general, without specifying gender.