Eurospeech 2001 - Scandinavia European Portuguese Nasal Vowels: An EMMA Study A. Teixeira and F. Vaz Instituto de Engenharia Electrónica e Telemática de Aveiro Departamento de Electrónica e Telecomunicações Universidade de Aveiro, 3810 193 Aveiro, Portugal, ajst@det.ua.pt Abstract In this paper new EMMA data regarding European Portuguese nasals is presented. Some details about corpus constitution, recording and annotation is given. First results from analysis are presented. Quantitative analysis of velum movement was done for nasal vowels between stops. For the other contexts represen- tative examples are presented and qualitatively analysed. In all contexts nasal vowels are produced with an initial phase having an high velum position. This result supports our previous work conclusions, of nasal vowels viewed as dynamic sounds were beginning must have dominant lips radiation. Obtained knowl- edge has application in articulatory synthesis, our motivation for this study. 1. Introduction Motivated by the need to improved quality of nasal sounds, class having special relevance for Portuguese, we have con- ducted several perceptual studies using articulatory synthesizer generated stimuli. One of the more important conclusions of our previous work is the important role of dynamics in the per- ception of Portuguese nasal vowels [1]. The use of velum and other articulators variation in time contributes to an improved naturalness of the articulatory synthesizer nasal vowels [2]. Our previous studies addressed three contexts for the nasal vowels: between two stops, after a nasal consonant, and iso- lated. In all contexts results point to Portuguese nasal having a diphthong like realization. They always start in a configura- tion making oral radiation dominant, and end in configurations with dominant nasal radiation [3]. This results are in accordance with the view of nasality “... as a dynamic trend from an oral configuration toward the pharyngonasal configuration” [4]. In order to pursue this line of work, we needed data about real production of Portuguese nasal vowels. We need informa- tion about tongue, jaw, lips and velum position both for oral and nasal vowels of Portuguese. Due to the relevance of dynamics, information of articulators variation over time was needed. Cur- rently EMMA is the best technique capable of providing such information. Main advantage of articulographic studies is that method is innocuous and gives real time measurements. The disadvantages are that measurements are generally limited to two dimensions and data is point-wise [5]. Due to the higher difficulty of velum measurements, there are not many examples of such data (an example is the MOCHA database [6]). For Portuguese there was none. This work was in part supported by Project P/PLP/11222/1998, Ar- ticulatory Synthesis of Portuguese, founded by Fundação para a Ciência e a Tecnologia, Portugal. 2. Data 2.1. Corpus Corpus was designed to (try to) answer to the following require- ments: 1. Type of velum variation in C ˜ V C sequences, where ˜ V is a nasal vowel and both C are stops. We are interested in duration of the initial part of of the vowel where velum stays closed or almost closed, opening speed/duration, and closing speed/duration; 2. Characterization of velum movement in sequences of nasal consonant followed by a nasal vowel; 3. Characterization of velum variation in nasal sounds at the end of words and sentences; 4. Characterization of velum and oral articulators variation in the pronunciation in isolation of a nasal vowel; 5. Characterization of velum and tongue variation in nasal diphthongs; 6. During [˜ e] and [õ] production oral articulators move pro- ducing sounds that should be described as [ ˜ e ˜ j] and [õ ˜ w]? In what contexts ? 7. Tongue position in nasal vowels and their corresponding oral vowels. This is particularly relevant for [õ] [˜] and [˜ e]; 8. Study of “nasal” vowels in words where there is doubt about their nasality. An example is “lã” [l ˜] (wool); 9. How is made the distinction between “amámos” and “amã- mos” (present and preterite of verb to love), This is a rare case of the utilization of oral/nasal contrast in a vowel between nasal consonants; 10. What happens in sequences like oral vowel followed by nasal vowel, nasal vowel followed by nasal consonant, and nasal vowel followed by other nasal vowel (in su- cessive words). This needs came from our work on articulatory synthesis. This kind of information is needed to synthesize Portuguese nasal vowels. Questions 1 to 3 are the most important. Last 3 only have a very limited utility. Because of that, and the recording process, corpus was divided in 2 parts: one, in Ta- ble 1, covering the most important needs, the other, in Table 2, completing the first part. Words from first part were pronounced without carrier sen- tence in groups of four words. Some of the words in the second part of the corpus, grouped in the table, were pronounced in a carrier sentence. Examples of words and phrases from corpora used, by Portuguese and