Analysis of Polish Nasalized Vowels Based on Spatial Energy Distribution and Formant Frequency Measurement.

In this paper, we discuss the results of the analysis of F1 and F2 frequency measurements in Polish nasalized vowels represented in writing by the graphemes e and a (realized before voiceless fricatives). The speech material included recordings of isolated word items provided by 20 adult native speakers of Polish (10 females and 10 males). According to the claims often presented in phonetic studies, the two vowels are phonetically realized as diphthongs composed of two subsequent stages of realization: an oral and a nasal stage. In our investigation, we refer to the results obtained by Lorenc et al. (cf. [13] and [14]) based on the analyses of spatial distribution of the acoustic field which indicate that the structure might be even more complex in certain cases and include three or even more stages. We measure formant frequencies within these stages using the stage timestamps obtained with a novel infrastructure composed of a multi-channel recorder with a circular microphone array. Among others, the results indicate that the two vowels differ significantly with regard to their internal structures as expressed by the number and types of the stages as well as frequency formant characteristics of those stages.