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The voiceless alveolar trill differs from the voiced alveolar trill /r/ only by the vibrations of the vocal cord. It occurs in a few languages, usually alongside the voiced version, as a similar phoneme or an allophone.
Proto-Indo-European *sr developed into a sound spelled ⟨ῥ⟩, with the letter for /r/ and the diacritic for /h/, in Ancient Greek. It was probably a voiceless alveolar trill and became the regular word-initial allophone of /r/ in standard Attic Greek that has disappeared in Modern Greek.
PIE *srew- > Ancient Greek ῥέω "flow", possibly
Features
Features of the voiceless alveolar trill:
Its manner of articulation is trill, which means it is produced by directing air over an articulator so that it vibrates.
Its phonation is voiceless, which means it is produced without vibrations of the vocal cords. In some languages the vocal cords are actively separated, so it is always voiceless; in others the cords are lax, so that it may take on the voicing of adjacent sounds.
It is an oral consonant, which means air is allowed to escape through the mouth only.
It is a central consonant, which means it is produced by directing the airstream along the center of the tongue, rather than to the sides.
The voiceless alveolar fricative trill is not known to occur as a phoneme in any language, except possibly the East Sakhalin dialect of Nivkh. It occurs allophonically in Czech.
Features
Features of the voiceless alveolar fricative trill:
Its manner of articulation is fricative trill, which means it is a non-sibilant fricative and a trill pronounced simultaneously.
Its phonation is voiceless, which means it is produced without vibrations of the vocal cords. In some languages the vocal cords are actively separated, so it is always voiceless; in others the cords are lax, so that it may take on the voicing of adjacent sounds.
It is an oral consonant, which means air is allowed to escape through the mouth only.
It is a central consonant, which means it is produced by directing the airstream along the center of the tongue, rather than to the sides.
Allophone of /r̝/ after voiceless consonants for speakers that do not merge it with /ʐ/. Present in areas from Starogard Gdański to Malbork and those south, west and northwest of them, area from Lubawa to Olsztyn to Olecko to Działdowo, south and east from Wieleń, around Wołomin, southeast from Ostrów Mazowiecka and west from Siedlce, from Brzeg to Opole and those north of them, and roughly from Racibórz to Nowy Targ. Most speakers, including speakers of standard Polish, pronounce it the same as /ʂ/, and speakers maintaining the distinction (which is mostly the elderly) sporadically do so too.
Asu, Eva Liina; Teras, Pire (2009), "Estonian", Journal of the International Phonetic Association, 39 (3): 367–372, doi:10.1017/s002510030999017x
Dankovičová, Jana (1999), "Czech", Handbook of the International Phonetic Association: A guide to the use of the International Phonetic Alphabet, Cambridge: Cambridge University Press, pp. 70–74, ISBN0-521-65236-7
