The Qiangic subgroup, the hypothesis of a common origin of thirteen Tibeto-Burman languages of Southwest China (e.g. Sun 2001), has come under much scrutiny in the past decade as more data on these languages have become available for fine-grained analysis and comparison. While it is now generally accepted that these thirteen languages mostly share only typological features, which does not constitute sufficient evidence for placing them together in a separate branch, there remains one phonological innovation proposed for the entire “Qiangic” subgroup by James A. Matisoff (2004): “brightening”, or a strong tendency for *-a, the best-attested rhyme in Proto-Sino-Tibetan (PST), to be raised and fronted to -i or -e. In the Sino-Tibetan context, this phonological tendency is quite exceptional, hence making it an interesting common trait of these languages and, if it really is a common innovation, evidence for the existence of the Qiangic subgroup. However, the phonetic basis of this unusual change, and the reasons for its inter- and intra-language variability, all remain without explanation. This paper presents a critical assessment of the phenomenon of “brightening”. We start with a small subset of Qiangic languages for which we have in-depth data: Ersu (Ganluo), Lizu (Kala, Ga’er, Mianning), and Duoxu (Mianning) (all “ELD” languages). We take as the starting point the original list of “brightened” forms presented in Matisoff (2004). We focus on cognate reflexes showing vowel raising in ELD languages (see 1-4), and provisionally set aside those forms where no brightening is evident in ELD (as in 5). No. Gloss PTB Ersu Kala Lizu Ga’er Lizu Mianning Lizu Duoxu 1 ‘bee/bird’ *bya bz̩̀ bǐ bi³³ `bi bi²¹ 2 ‘wear’ *gwa ʒź̩ [dê-]wu [da³³-]vu⁴⁴ `[de-](ɣ)we, `[de-]vʉ ve²² 3 ‘nose’ *s-na ~ *s-na:r sú[mbú] tô[mbu] ke³³[mɐ⁴⁴] `ʃti[mbʉ] nja³¹[ku⁵³] 4 ‘frog’ *bal pź̩[má] pi[mæ̂] pe³³mje⁴⁴ pimæ pa³³[ma⁵³] 5 ‘come’ *la là lǎ læ³³ læ la²¹ Based on this data, we argue that the “brightened” reflexes essentially fall into two groups: (1) Vowel raising can be correlated with the presence of a glide with high tongue position (j, w) in the reconstructed PST form (as in 1-2). (2) Vowel raising can be correlated with the presence of a nasal element. That nasal element can be part of the initial cluster in the reconstructed PST form (as in 3); and/or be the initial of the second syllable in the modern disyllabic form (as in 4). Vowel raising in these two groups is likely due to two unrelated processes. In the former group, it can be attributed to the assimilatory effects that glides with high tongue position have on neighboring vowels, as is common both cross-linguistically (e.g. Ladefoged & Maddieson 1996: 286-288) and in neighboring non-Qiangic languages (Chirkova & Handel 2013). In the latter group, it is argued to be a compensatory mechanism to attenuate the acoustic effect of nasalization and thus, resist the phonologization of vowel nasalization in ELD. ELD languages are characterized by the absence of both nasal codas and phonemic nasal vowels. Previous studies demonstrate that nasalization can lead to the lowering of high vowels and the raising of low vowels (Beddor 1983; Carignan et al. 2012). An effect on spectral changes along F1 similar to that caused by nasalization can also be independently achieved through changes in oral configuration (tongue height and jaw position) (e.g. Beddor et al. 1986; Krakow et al. 1988: 1146; Shosted et al. 2012). Given that F1 can be independently modulated by these two articulatory mechanisms, it may be possible for listeners to confuse them when attending to nasal vowel quality (e.g. Wright 1986: 54-55). Misinterpretation of nasalization in terms of oral configuration typically arises when nasal coupling is excessive or when nasalization occurs without a conditioning environment (Beddor et al. 1986: 214; Krakow et al. 1988). In ELD languages, it is likely correlated with the loss of original nasal codas and the simplification of PST initial clusters containing nasals. As the examples in the chart above show, the degree to which vowel raising is produced and perceived in ELD varies from language to language and from dialect to dialect. That likely reflects synchronic variation inherent in coarticulatory phenomena such as contextual palatalization and vowel nasalization. As a result, varieties of a language may differ in terms of degrees of gestural overlap in consonant-vowel sequences. A review of “brightened” forms in other Qiangic languages supports our analysis in terms of coarticulatory processes: (1) tongue body raising and fronting due to the presence of a glide involving high tongue position; (2) tongue body raising and centering as a compensatory strategy for vowel nasalization. Such coarticulatory effects characteristically exhibit language-dependent differences in degree of vowel raising and fronting. Language-specific syllable structure constraints also appear to play a role, such as the presence of nasal codas and phonemic nasal vowels. For example, Shuhi (a.k.a. Shixing), which has phonemic nasal vowels, only exhibits effects of vowel raising due to the presence of a glide. The paper is concluded by a discussion of (i) exceptional etyma that show the effects of “brightening” in ELD while not falling into either of the two groups discussed above (e.g. PST *tsa ‘salt’: Ersu /tsʰz̩̀/, Lizu /tsʰə́/, Duoxu /tɕʰi³³/); (ii) etyma that do not show the effects of “brightening” in ELD, but do have “brightened” reflexes in some other Qiangic languages (e.g. PST *la ‘come’).