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Abstract. This study describes the acoustic properties associated with tone and register in Louma Oeshi, a previously unstudied Akoid language of Laos. Louma Oeshi uses three tones (High, Mid, and Low) which overlap with a tense/lax register distinction to yield a six-way suprasegmental contrast. In this paper, we (1) offer a first account of the pitch and voice quality characteristics associated with each Tone-Register pair, (2) examine further the variability in glottalization strategies signaling the constricted register, and (3) explore the influence of contrastive voice quality on pitch and vice versa, particularly as a predictor of the variation in glottalization.Keywords. tone; register; voice quality; Tibeto-Burman; Louma; Oeshi 1. Introduction. This study describes the acoustic properties associated with tone and register in Louma Oeshi (henceforth Oeshi), a previously unstudied Akoid/Hanoid language in Laos, belonging to the Southern Lolo/Ngwi subgroup of Tibeto-Burman. Like other Southern Ngwi languages, Oeshi phonology employs three tone levels (High, Mid, and Low) and an overlapping a tense/lax register distinction. In the case of Oeshi, tone and register are fully intersective such that they combine to yield a six-way suprasegmental contrast. In recent decades, the phonetic literature has shown that the boundary between what have traditionally been known as "tone" and "register" languages is often quite blurred, particularly in languages of mainland Southeast Asia (Abramson & Luangthongkum, 2009). How a mixed tone-register prosodic system weighs or emphasizes its multiple contrasts has become an issue of great interest to both phoneticians and phonologists (Silverman 1997 The complete intersection of tone and register levels in Oeshi (Lax and Tense register co-occur with each Low, Mid and High tone) indicates that the qualities are phonologically independent in the sense of Kuang (2013), but raises questions about their phonetic interaction. In addition to providing a first account of Oeshi tonal phonetics, this paper explores how voice quality settings affect pitch across the tone-register combinations, and vice versa. The preliminary data presented here suggests that pitch and voice quality are mostly independent in their phonetic production as well. That is, Oeshi speakers manipulate pitch or voice quality characteristics without great influence on the other property. There is, however, a substantial exception to this observation --High Tense tone-register words, which are noteworthy for a variety of reasons.The paper proceeds as follows. We first describe the relationship of Oeshi to other regional languages with similar, but importantly different, complex tone-register systems ( §2). After explaining our experimental methods and analytic techniques ( §3), we provide the findings ( §4) for the two most successful acoustic correlates of the six-way prosodic contrasts: F0, the fundamental frequency of the acoustic signal (tone) and *H1-H2, the

Louma Oeshi is an Akoid (Tibeto-Burman) language of Laos for which acoustic characteristics are undocumented with the exception of preliminary work by the present authors. This study focuses on the phonetic properties associated with Oeshi's three tones (high, mid, and low) and two registers (Tense, Lax), which fully intersect to yield a six-way suprasegmental contrast. Eight speakers were recorded in Phongsali Province, Lao PDR. Each spoke a 100 token word list, for which 30 tokens were repeated in a carrier sentence placing the token between high and mid-toned lax words. Decile measures of F0 and an array of measures reflecting phonation types (H1-H2, H1-A1, H1-A3, HNR, and SHR) were performed in Voicesauce (Shue et al. 2011) to capture dynamic values over the syllable duration. Our findings show a reliable three-way F0 contrast between tones and a single interaction with register such that High Tense words consistently fall (tones are otherwise level). Acoustic correlates of the Tense~Lax distinction are less clear. The picture that emerges is one where Tense register has variable phonetic manifestations — preglottalization of onsets, vocalic creaky voice, or a glottal stop coda — and the seemingly inconsistent acoustic results reflect these variable articulatory timing strategies.

Cross-linguistically, fricatives are the rarest types of rhotics, found in a few African and European languages (Ladefoged & Maddieson 1996) and as allophones in some Romance languages (Jesus & Shadle 2005; Recasens 2002; Bradley 2006; Colantoni 2006). Acoustic data from Nusu, phonotactic reasoning, and a cognate comparison demonstrate the presence of alveolar fricative rhotics in Tibeto-Burman. The Nusu rhotic appears in syllable-initial position as the first or second consonant and can be realized as alveolar approximants [ɹ] or [ɹʲ], non-sibilant voiced and voiceless fricatives [ɹ̝, ɹ̥], as well as voiced sibilant [ʐ]. In other studies on Nusu, these fricative rhotics have sometimes been reported as retroflex voiced sibilants (Sun & Lu 1986; Fu 1991), but intra-speaker and cross-variety comparison point to classification as rhotics. Evidence from other Tibeto-Burman languages suggests that alveolar fricative rhotics are not limited to Nusu. Together these data challenge the tradition of generally interpreting alveolar fricatives as sibilants.