In a study of European Portuguese fricatives it was noted that /ʀ, ɾ/ were often realized as [χ, ʁ, ɾ̥], which are, respectively, unvoiced and voiced uvular fricative, and voiceless tapped alveolar fricative. Although these phones have not previously been recognized as occurring in European Portuguese, they occurred in 115 words out of a corpus of 1304 words, out of which 107 words could be analysed, in recordings made by four native speakers (two men, two women). Time- and frequency-averaged power spectral characteristics are presented, together with a detailed temporal analysis. The frequencies of high-amplitude peaks in the [χ] and [ʁ] spectra clearly indicate a back place of articulation, with median duration across subjects and words of 69 ms and 35 ms. The short (approximately 20ms), noisy acoustic signal in [ɾ̥] suggests a stop-like manner of articulation, but the turbulence noise characteristics, similar to fricatives, differ from the transient burst noise of plosives.
Journal of the International Phonetic Association 35(1)