As I understand it, a question like “Der Wievielte ist heute?” can be used to inquire about the date. Are there other phrases in German like this that seem to take an interrogative word or phrase like wie viel and convert it into something that looks like an adjectival noun (der wie-viel-te)? If not, does anyone have sources on the origin of the phrase or in what contexts it’s used?
So as you say, wievielt is an adjective, which can of course be used in many other situations. Take your example, which nounifies it: der Weivielte ist heute? This could be re-written in in its adjectival form: (der) wievielte Tag des Monats ist heute?
If playing around with this as a noun or an adjective, one musn't forget: if you transform an adjective it into a noun (as can be done with almost any adjective: see the third example below), then it requires a capital letter. Here are some comparable uses:
- beim wievielten Versuch hat er es endlich geschafft?
- das wievielte Mal bist du jetzt dort gewesen?
- das ist ja doch etwas Besonderes
It is formed analogously to the ordinal numbers, e.g. first/erster, second/zweiter and which (read: the how-many’th)/wievielter. [all German versions shown in the masculine singular, the der form].
As to there being comparable constructions out there… I am sure there are. The issue here is, however, that interrogatives produced from several words are few and far between — wie viel is the only multi-word interrogative (that I can think of).
Other words look like they may have followed a similar path to becoming an adjective, just like wievielter, e.g. current/derzeitiger and diverse/vielfältiger (~ many-sided).
Notice that derzeitig is a combination of the words die and Zeit, rounded off with the ig adjectival ending. The die must however appear in the genitive, as it belongs to the noun it describes. Example:
Die derzeitige Zeitung --> Die Zeitung der Zeit --> The newspaper of the time
The current newspaper
Some speakers accept W-words at basically any position, such as verbs. E.g. here:
„Du wurdest hier getagged.“
„Ich wurde gewast?“
This is colloquial, and speakers will vary in their acceptance of this phrase. But I’d argue it’s near universally understood, at least spoken (it needs the question emphasis, and it helps to not have the low-frequency orthography make it stand out).
Across languages, this is not particularly strange — Chinese questions are formed by replacing, in the same position, the word the question is about with a question word and leaving the rest of the sentence as-is. But in standard, especially written, German, the construction is more limited.