Learn Hardcore German: Die Zuschauerin wartet geduldig vor der Bühne. - The female spectator waits patiently in front of the stage.

Zuschauerin is the explicitly feminine form of Zuschauer (viewer, spectator). The suffix -in marks female persons; the plural is Zuschauerinnen. German often uses the generic masculine (Zuschauer) for mixed or unspecified gender, but inclusive forms like Zuschauerinnen und Zuschauer or Zuschauer:innen are also common.

Why do I see both die and der in one sentence?

They’re different cases of the definite article for feminine nouns:

die Zuschauerin = nominative singular (the subject).
vor der Bühne = dative singular (required by the preposition vor when it expresses location). So der here is the dative feminine article, not masculine.

Why does vor take the dative here?

vor is a two-way preposition. It takes:

Dative for location (Where? static position): vor der Bühne.
Accusative for direction (Where to? movement): vor die Bühne.

When would it be vor die Bühne instead?

Use accusative for movement toward the front of the stage, e.g. Sie geht vor die Bühne (She goes to the area in front of the stage). Once she is there, you’d switch back to dative: Sie steht vor der Bühne.

Why not wartet auf here? Isn’t warten auf “to wait for”?

Two different things:

warten
- place phrase = where someone is waiting: Sie wartet vor der Bühne.
warten auf
- accusative = what or whom someone is waiting for: Sie wartet auf ihren Freund / auf den Beginn der Show. You can combine both: Sie wartet vor der Bühne auf ihren Freund.

Where can geduldig go in the sentence? Is the order fixed?

Default and most natural is verb + manner + place (follows the TeKaMoLo tendency: Time–Cause–Manner–Place):

Die Zuschauerin wartet geduldig vor der Bühne. For emphasis, you can front the adverb or the place:
Geduldig wartet die Zuschauerin vor der Bühne.
Vor der Bühne wartet die Zuschauerin geduldig. All are correct; word order shifts nuance and focus.

Is geduldig an adjective or an adverb here?

It’s the adjective geduldig used adverbially. In German, adjectives used adverbially are uninflected: Sie wartet geduldig. Attributively before a noun, they take endings: eine geduldige Zuschauerin. Predicatively after sein/bleiben/werden they are also uninflected: Sie ist geduldig.

How do you pronounce Bühne, and what does ü sound like?

Bühne is [ˈbyːnə]. The ü is a front, rounded vowel—shape your lips for English “oo” but keep your tongue position like English “ee.” Don’t confuse Bühne (stage) with Buhne (a coastal groyne), which has plain u.

Is warten regular? How is it conjugated?

Yes, it’s regular. Present tense:

ich warte
du wartest (extra e for pronunciation)
er/sie/es wartet
wir warten
ihr wartet
sie/Sie warten Simple past: wartete. Past participle: gewartet. Auxiliary: haben (e.g., Sie hat lange gewartet).

What changes in the plural?

Subject plural: Die Zuschauerinnen warten … (verb becomes plural). If there’s still one stage: … vor der Bühne. If multiple stages: … vor den Bühnen (dative plural article den; nouns usually take an extra -n in dative plural if they don’t already have one—Bühnen already ends in -en).

Could I use an or bei instead of vor?

vor der Bühne = in front of the stage (facing it). This is the standard choice here.
an der Bühne = at/by the stage (touching/at the edge; less common for audience position, more for crew/backstage contexts).
bei der Bühne = near the stage (in the vicinity, not necessarily in front).

Can I use the indefinite article or add adjectives?

Yes:

Eine Zuschauerin wartet geduldig vor der Bühne.
Eine geduldige Zuschauerin wartet vor der Bühne. With an attributive adjective, make sure the ending matches the article and case.

What’s the difference between Zuschauerin and Zuhörerin?

Zuschauerin = a female viewer/spectator (visual focus; theatre, sports, shows).
Zuhörerin = a female listener (audio focus; lectures, radio, podcasts). At a concert you might use either, but with Bühne the visual angle makes Zuschauerin more typical.

Why are Zuschauerin and Bühne capitalized but geduldig isn’t?

All nouns are capitalized in German: Zuschauerin, Bühne. Verbs and adjectives are not, unless they start a sentence or are part of a proper noun. So geduldig stays lower-case here.

How do I know Bühne is feminine?

You usually learn the article with the noun. A common pattern is that many nouns ending in -e are feminine (e.g., die Schule, die Lampe, die Straße), though there are exceptions. Dictionaries mark gender; memorize nouns with der/die/das.