What’s in the r? A review of the usage of the r symbol in the Illustrations of the IPA

What does the symbol r mean when it is used in a transcription? Here we analyze the use of the symbols for the alveolar trills (r) and taps ( ) among the Illustrations of the IPA since 1971. We begin by sketching the history of the various symbols and conventions used to represent the trill and the tap in two transcription traditions: the Americanist Transcription System and the International Phonetic Alphabet. From the 213 languages covered until 2021, we carefully analyze the 162 that have trills and/or taps, using the information provided in Illustrations. Our results show that r tends to be used to represent a generic ‘r-like’ sound in both transcription traditions. More precisely, by comparing the use of r in the consonant tables and in the transcriptions of their accompanying narrative texts, we show that r is not systematically associated with an alveolar trill. Furthermore, we show that phonetic trills are less frequent than phonetic taps, while phonemic trills are more frequent than phonemic taps. As a consequence, inferring the presence of trilling in a sound system from the presence of r in its transcription is not as straightforward as one might expect. These findings highlight the critical importance of being absolutely explicit about the meaning of the various symbols found in grammars and secondary databases, and of r in particular, as a preliminary step in a broad range of studies, including cross-linguistic comparisons, inferences about the past or generalizations about language acquisition and articulatory effort.