In search of the Austronesian L: A phonetic reconstruction of Proto-Austronesian laterals

Abstract: While many aspects of the Proto-Austronesian (PAn) consonant inventory remain disputed in terms of reconstruction, there is a general consensus that it likely included two lateral consonants, often called *N and *l. Various phonetic values have been proposed for these phonemes, with *N perhaps having been a lateral fricative, and *l a retroflex lateral or non-lateral flap. Since PAn *N merges into *n as a nasal in Proto-Malayo-Polynesian, the reflexes of *N and *l in Formosan languages that reflect them as independent lateral sounds are of special importance when it comes to their phonetic reconstruction. In this study, experimental phonetic data is collected using electromagnetic articulography and ultrasound tongue imaging from speakers of Rukai and Puyuma, two Formosan languages believed to be conservative in their articulation of these two phonemes. Results show that both languages share several key phonetic features in both phonemes, supporting the reconstruction of *N as a laminal dental sound and *l as a retroflex sound. In addition to their place of articulation, lateral movement of the tongue is also examined and used to confirm that the reflexes of *l are lateral approximants in both languages, despite their description as a non-lateral flap in some sources. Key differences in their articulation, such as their difference in place of lateralization, may explain why these two laterals do not merge in any known daughter language. Similarities in place of articulation and tongue shape between the reflexes of *N and *n are also observed, suggesting their frequent merger in the family as being due to similarities in articulation. These results provide additional support for the reconstruction of a dental versus retroflex contrast in coronal consonants in PAn.