Stage German (German: Bühnendeutsch, [ˈbyːnənˌdɔʏ̯t͡ʃ] or Bühnenaussprache [ˈbyːnənˌʔaʊ̯sʃpʁaːxə], English: stage pronunciation) is a unified German set of pronunciation rules for the German literary language used in the theater of the German-speaking countries, which was established in the 19th century. Stage German is mostly based on the Northern Standard German phonology, and won a great reputation as a pure High German during that century. An example of this is the pronunciation of the suffix -ig pronounced like [ɪç].
Until 1957, only two pronunciations were allowed: an alveolar trill [r] and an alveolar tap [ɾ]. After 1957, a uvular trill [ʀ] was also allowed. A voiced uvular fricative [ʁ], used extensively in contemporary Standard German, is not allowed. Therefore, e.g. rot 'red' can be pronounced [roːt], [ɾoːt] and [ʀoːt], but not [ʁoːt].
The vocalized [ɐ̯] realization of /r/ found in German or Austrian Standard German corresponds to [r ~ ɾ ~ ʀ] in Bühnendeutsch, so that e.g. für 'for' is pronounced [fyːr ~ fyːɾ ~ fyːʀ], rather than [fyːɐ̯].
Whenever the sequence /ər/ is vocalized to [ɐ] in German or Austrian Standard German, Bühnendeutsch requires a sequence [ər ~ əɾ ~ əʀ], so that e.g. besser 'better' is pronounced [ˈbɛsər ~ ˈbɛsəɾ ~ ˈbɛsəʀ], rather than [ˈbɛsɐ].
In contemporary Standard German, both of these features are found almost exclusively in Switzerland.
Contrary to Standard German, /ə/ cannot be elided before a sonorant consonant (making it syllabic), so that e.g. Faden 'yarn' is pronounced [ˈfaːdən], contrasting with the standard [ˈfaːdn̩].
In loanwords from Latin and Ancient Greek, the word-final /ə/ is realized as a short tense [e], so that e.g. Psyche 'psyche' is pronounced [ˈpsyːçe], rather than the standard [ˈpsyːçə].
As in Standard Northern German, syllable-final obstruents written with the letters used also for syllable-initial lenes (⟨b, d, g⟩ etc.) are realized as fortis, so that e.g. Absicht 'intention' is pronounced [ˈʔapz̬ɪçt] (note full voicing of /z/, which, in position immediately after fortes, occurs only in Bühnendeutsch - see below), whereas Bad 'bath' is pronounced [baːt].
The corresponding standard southern (Southern German, Austrian, Swiss) pronunciations contain lenis consonants in this position: [ˈab̥z̥ɪçt ~ ˈab̥sɪçt] and [b̥aːd̥], respectively.
The voiceless plosives /p, t, k/ are aspirated [pʰ, tʰ, kʰ] in the same environments as in Standard German, though more strongly - this applies especially to environments, in which the Standard German plosives are aspirated moderately and weakly, e.g. in unstressed intervocalic and word-final positions. This can be transcribed in the IPA as [pʰʰ, tʰʰ, kʰʰ]. The voiceless affricates /p͡f, t͡s, t͡ʃ/ are unaspirated [p͡f˭, t͡s˭, t͡ʃ˭], as in Standard German.
The lenis obstruents /b, d, ɡ, d͡ʒ, v, ð, ʝ, z, ʒ/ are fully voiced [b̬, d̬, ɡ̬, d̬͡ʒ̬, v̬, ð̬, ʝ̬, z̬, ʒ̬] after voiceless obstruents, so that e.g. abdanken 'to resign' is pronounced [ˈʔapd̬aŋkən]. This is in contrast with the Standard Northern pronunciation, which requires the lenes to be devoiced in this position: [ˈʔapd̥aŋkn̩]. Southern standard accents (Southern German, Austrian, Swiss) generally realize the lenes as voiceless in most or all positions, and do not feature syllable-final fortition: [ˈab̥d̥aŋkn̩].