Duration and Phonological Complexity: Comparing standard European Portuguese nasal vowels and oral diphthongs

International audienceNasal vowels have been described as being long and having a diphthong-like acoustic pattern. They are therefore a complex topic both for phonetic description and phonological analysis. Phonologically, it’s been proposed that nasality is directly associated (a) to the vowel /Ṽ/; (b) with an underlying nasal consonant in coda position /VN/; or (c) with a vocalic position in a complex nucleus /VṼ/. Even if (b) is the most commonly accepted proposal, the behaviour of nasal vowels allows eliminating both (a) and (b), which leads to proposal (c).Nasal vowels and oral diphthongs share some properties, such as behaving as heavy rhymes regarding stress assignment; allowing suffixation of morpheme /-s/ without epenthesis; showing no resyllabification in external sandhi context; other than the fact neither undergoes vowel reduction in unstressed positions.Assuming that length can be a correlate to phonological complexity, (c) will be supported if, in addition to the other similarities between diphthongs and nasal vowels, those objects are similar in length. To my knowledge, the length of Portuguese nasal vowels has never been compared to that of complex nuclei. To assess the respective length of nasal vowels and oral diphthongs, I compare the duration of oral vowels (V), nasal vowels (VN) and oral diphthongs (VG) in two contexts: word-finally (_#), and before a heterosyllabic consonant (_t, _s). Results show that oral vowels are statistically shorter than oral diphthongs, which have the same duration as nasal vowels (i.e. V < VG = VN). This clearly gives a phonetic grounding for the representation of Portuguese nasal vowels as phonological diphthongs.Finally, I call the attention to three facts: (i) while oral diphthongs behave as open syllables regarding rhotics, allowing a contrast between /ɾ/ and /ʀ/, nasal vowels trigger neutralization, just as coda consonants; (ii) Portuguese also has nasal diphthongs, which are almost in complementary distribution with nasal vowels, since the latter exist in all positions but are clearly dispreferred in final position, while the former are found almost exclusively in stressed final position; (iii) in non-standard variety, nasal vowels and diphthongs can alternate. I propose a phonological representation of Portuguese nasality that motivates both the similarities and the differences between oral diphthongs and nasal vowels