modern German declension

[Beli Orao]

So the distinctions between cases in German are made mostly by articles, right? Is there a name for this phenomenon? At what stage in the development of the language did it arise? Are there any parallels in other Germanic languages?

[Jipí]

Declension by means of articles existed already in Middle High German (i.e. ~1050-1350), but not in Old High German (~750-1050, though note that there's hardly anything in German during the reign of the Ottonians because they preferred Latin). Basically, the only thing about definite articles that changed in 800 years is diu /dy:/ > die /di:/. Declension of other determiners/modifiers (indefinite articles, adjectives, possessives, demonstratives) changed a little more, though. As for whether there's a special term for declension by article, I don't know.

[Yng]

Yeah, all that basically happened as far as I can tell is that whilst sound change (particularly final unstressed vowels turning to schwas, m and n becoming confused etc) pretty much killed off noun declension (or at least simplified it to the point where analogy could do the rest - technically in modern German the dative CAN be distinguished on a lot of nouns by suffix, but I'm told it sounds tremendously stuffy - at least in the singular), but did not have the same effect on articles, which remained, comparatively, highly distinct. It's not so much that declension necessarily shifted to articles, AFAIK, but more articles developed which agreed in case and, at the same time or perhaps later, noun declension was levelled significantly.

[Jipí]

Dative -n is required for some nouns.

[Yng]

Dative -n is required for some nouns.

Is that in the singular? I thought it was just in the plural?

[Jipí]

No, see here: http://goo.gl/0Yazj

[Yng]

Ahh, weak nouns. True, but they vary only based on nom/non-nom, right?

[Jipí]

Da bin ich überfragt

[Yng]

Well from the page you linked, they do.

If I'm right, nouns in German basically break down into:

Masculine/neuter

Strong nouns with a plural in -(e)n or -s, which decline (NOM ACC DAT GEN) -ø -ø -ø/-e -(e)s -PLU -PLU -PLU -PLU - e.g.
Strong nouns with any other native plural, which decline -ø -ø -ø/-e -(e)s -PLU -PLU -PLU-n -PLU
Weak nouns, which decline -ø -(e)n -(e)n -(e)n -(e)n -(e)n -(e)n -(e)n

The -e in the singular being semi-archaic at least.

Feminine

Strong nouns with a plural in -(e)n or -s, which decline (NOM ACC DAT GEN) -ø -ø -ø -ø -PLU -PLU -PLU -PLU
Strong nouns with any other native plural, which decline -ø -ø -ø -ø -PLU -PLU -PLU-n -PLU

With feminine declension being characterised by the lack of distinct singular endings for either the dative or genitive.

So for example:
das Mädchen, das Mädchen, dem Mädchen, des Mädchens, die Mädchen, die Mädchen, den Mädchen, der Mädchen
das Kind, das Kind, dem Kind(e), des Kindes, die Kinder, die Kinder, den Kindern, der Kindern
der Name, den Namen, dem Namen, des Namen, die Namen, die Namen, den Namen, der Namen

die Katze, die Katze, der Katze, der Katze, die Katzen, die Katzen, den Katzen, der Katzen
die Stadt, die Stadt, der Stadt, der Stadt, die Städte, die Städte, den Städten, der Städte

But there is Herz which you pointed out is irregular and acts like a weak noun everywhere except the accusative and the genitive, and some others as well.

[hwhatting]

Weak nouns, which decline -ø -(e)n -(e)n -(e)n -(e)n -(e)n -(e)n -(e)n

der Name, den Namen, dem Namen, des Namen, die Namen, die Namen, den Namen, der Namen

Your example is wrong - there is a small group of weak male nouns that goes N -e, DA -en, G -ens, and Name belongs to that group; others are Friede "peace", Drache "dragon".*)
A better example would have been Erbe "heir".

*) All these words can also be declined like Balken, Rechen etc. - i. e. -en in all case and number forms except except Gen. sg. -ens. Nom. Namen is frequently found in colloquial registers, Frieden is now the standard literary form while Friede is poetic / old-fashioned, if not archaic; in the literary language, Drache is only used for "dragon", while Drachen is the only admissible form for the meaning "kite" (but it can be used for "dragon" as well, especially in the colloquial language). In any case, a gen. *des Namen doesn't exist in Standard Modern German.
(Now that I think of it - Drache can also take the Gen. Sg. in -en).

[Jipí]

To save my butt: Yng asked me whether he was right on IRC after he'd written that, I said yes, but I must've overlooked the one with "Name"