This week we are going to take a look at the differences between dann and denn, a fairly difficult topic even for experienced non-native German speakers. Part of the problem lies in the fact that in Old High German and Middle High German, these two currently distinct words were just one word, thus they both come from the same root. If we reduce dann and denn to their basic grammatical forms, it's possible to get a better understanding of how they are used.
1. As an adverb, dann is usually translated as "then":
Wenn die Klassen größer werden als 15 bis 20,
When the classes get bigger than 15 to 20,
dann fange ich an zu teilen.
then I start to split them.Play Caption
Dann ist auch die Mutter damit beschäftigt, Nahrung herbeizuschaffen.
Then the mother is also occupied with providing nourishment.
Caption 31, Alpenseen - Kühle SchönheitenPlay Caption
If you ever hear a native German say denn as an adverb in sentences similar to the above, that's because in Northern German dialect, denn and dann are still interchangeable. According to Duden, any other use of denn as an adverb is only very rare.
2. As a particle, denn is usually translated as "then":
Und was ist denn los?
And what is happening then?
Caption 45, Das Lügenbüro - Die BewerbungPlay Caption
Wo wollen wir denn hin?
Where do we want to go then?
Caption 30, Die Klasse - Berlin '61Play Caption
Note that the particle denn is almost exclusively found in interrogative sentences (sentences that ask a question)!
3: As a coordinating conjunction, denn is usually translated to English as "because" (or sometimes "since"):
Wir erleben Emotionen und heben ab, denn wir sind frei.
We experience emotions and lift off, because we are free.
Caption 12, Christina Stürmer - FieberPlay Caption
Denn plötzlich wurden wir eine richtig moderne Familie.
Because suddenly we became a really modern family.Play Caption
Notice that denn is a conjunction like und or aber or oder and does not force the sentence order to place the verb at the end of the sentence.
So to recap:
1. dann as an adverb usually translates as "then";
2. denn as a particle is usually found in sentences asking a question and usually translates as "then," though as an emphasis word it may not be translated at all;
3. denn as a conjunction usually translates as "because," except in
4. Northern German dialect, where denn is used interchangeably for the standard German adverb dann.
Perhaps the easiest way to remember the basic gist of this is: if you want to say "then" in a sentence, it's usually dann; if you want to say "then" in a question, it will most often be denn; or if you want to say "because" you can use denn. This is somewhat oversimplifying the situation, but should serve as a good way to sort out the basics of the differences between dann and denn!
In next week's lesson, we will learn about the difference between the conjunctions denn and weil, both ways to say "because."
Go to Yabla German and search for dann and denn to see the words used in a real-world context. For an in-depth analysis of the origin of the words dann and denn, read this DWDS page under Etymologie, and be sure and click below it for the full version of the text! For a somewhat lighter-hearted view on the two words, check out this German language blog.
The word sei is something that can be a bit confusing when it appears. Although it is rare and more often used in written German, sei does comes up on Yabla German every once in a while.
It is, for one, the informal second person command form of the verb sein ("to be").
Wir haben Fieber, komm sei dabei
We have the fever, come be involved
Caption 11, Christina Stürmer - FieberPlay Caption
Sei ruhig, Findus, ich bin ja noch gar nicht aufgestanden.
Be quiet, Findus, I indeed haven't gotten up yet at all.
But sei appears in other contexts as well. The phrase es sei denn can be translated as "unless":
Man hat uns erzählt, sie läge bis zum heutigen Tag dort,
Someone has told us [it is said] that it is there to this very day,
es sei denn, es hat sie jemand gegessen.
unless someone has eaten it.
Captions 93-94, Märchen - Sagenhaft - Die Prinzessin auf der ErbsePlay Caption
Sei is particularly used when something is or was reported or thought to be true, but isn't proven. However, it is used most often in written German, or narration and reporting.
Also hat der Papst die Armbrust verboten
So the Pope forbade [the use of] the crossbow
und hat gesagt, es sei ein Werkzeug des Teufels.
and said it is a tool of the devil.
Captions 30-31, Die Armbrust - im MittelalterPlay Caption
Nein, der unbekannte Verkehrsteilnehmer hatte nur irrtümlich angenommen, die Parkuhr sei beschädigt...
No, the unknown motorist had just mistakenly assumed the parking meter was damaged...
Die böse Königin glaubte, Schneewittchen sei tot...
The evil Queen believed Snow White to be dead...
Caption 51, Märchen - Sagenhaft - SchneewittchenPlay Caption
Do you know all of the conjugations of sein in the imperative? If not, review them now with the table on this page. When you encounter sei in its other contexts, remember that it essentially communicates the subjunctive and what is being said may not be true at all!