In German the phones [r], [ʀ] and [ʁ] are free allophones of the phoneme /r/.
- phone
A phone is a distinct sound, i.e. noticeable different from other sounds, that is used to speak.
- phoneme
An abstract class of sounds that is able to distinguish a word from another in a certain language, i.e. if the pronunciation of two words is equal except of only one sound, then those sounds are representatives of different phonemes in a certain language if the two words have different meanings. The two sounds are representatives of the same phoneme in this language if the two pronunciations are just variations of the same word.
- allophone
Allophones are two or more different phones that belong to the same phoneme in a certain language.
Allophones again are departed in two groups:
- allophones with free variation (sometimes also: free allophones)
When the phones that belong to the same phoneme can be interchanged without having to obey any other rules, then they are free allophones. This means, that in each word where one of those phones is used, it can always can be replaced by another allophone.
Since in German [r], [ʀ] and [ʁ] are free allophones, all of the following pronunciations are correct and have the same meaning:
rot = [roːt], [ʀoːt], [ʁoːt]
kurz = [kʊrʦ], [kʊʀʦ], [kʊʁʦ]
- allophones with combinatoric variation (sometimes also: bound allophones)
Examples for this kind of allophones are in German: [ç] and [χ] which are used to pronounce the digraph »ch« (like in »dich« or »doch«). After bright vowels like /ɪ/ only [ç] can appear, after dark vowels like /ɔ/ only [χ].
dich = [dɪç]
doch = [dɔχ]
The fact, that German has three freely interchangeable phones ([r], [ʀ] and [ʁ]) that can realize the same phonem (/r/) does not mean, that you will hear all of them in all words. This highly depends on the speaker. Lots of German native speakers are not able to produce the sound [r] (»gerolltes R«), so they only can use the other two phones.
The most often used realization of the phoneme /r/ in German language is the phone [ʁ].
description of [r], [ʀ] and [ʁ]
- [r]
Voiced alveolar trill
The tip of the tongue touches the teeth-ridge (the bulge behind the incisors) and air flows through this gap, so that the tip of the tongue vibrates.
- [ʀ]
Voiced ulvular trill
Here the back (dorsum) of the tongue and the uvula forma gap, and air flowing through this gap lets the uvula vibrate.
- [ʁ]
Voiced uvular fricative
Also here its the back of the tongue and the uvula that form a gap. But the air doesn't make the uvula vibrate, so there is no trill sound. But the air flows turbulent through this gap, which produces a fricative sound.