Seiya Funatsu

A study of data normalization measured by an electro-magnetic articulograph

We investigated the normalization of the data measured using an electro-magnetic articulograph (EMA). The data normalization was needed because the size of the articulator of each subject is different from the sex and/or body size. Moreover, tongue movement range depends upon the speaking styles, clear or unclear. Our experiments were as follows: tongue tip movements during articulation of non-native consonant clusters were measured. Speakers were 2 Japanese and 2 Germans. Speech samples were 4 nonsense words, bnaht, pnaht, gnaht, knaht. Tongue tip displacement D (mm) and moving time T (ms) between first and second consonant in consonant clusters were measured. Dx (X component of D) was normalized by the difference between maximum value of X (Xmax) and minimum value of X (Xmin) in each utterance, i.e. Dnx=Dx/(Xmax-Xmin). Also Dy (Y component of D) was normalized, i.e. Dny=Dy/(Ymax-Ymin). Hence, Dn (normalized D) was Dn=(Dnx2+Dny2)1/2. T was normalized by word length L (ms), i.e. Tn=T/L. Before the normali...

Difference of articulatory movement between native and non-native consonant clusters

We investigated the difference of articulatory movement between native and non-native consonant clusters. English has consonant clusters, but Japanese does not. Therefore, speakers chosen for comparison were native English and native Japanese speakers. Speech samples consisted of 4 words, “blat,” “bnat,” “plat,” “pnat.” In these words, /bl/ and /pl/ are English clusters, but /bn/ and /pn/ are not. We measured the movement of the tongue tip, the mandible and the lower lip by WAVE system (NDI corp.). There were remarkable differences in the mandible and the lower lip movement between native (/bl/, /pl/) and non-native (/bn/, /pn/) clusters in English speakers. Namely, with the non-native clusters the difference of the articulatory movement in the mandible and the lower lip of every utterance was quite large; however, in native clusters, the difference was quite small. For Japanese speakers it was large for all clusters. Thus, it was revealed that the articulatory movement of the mandible and the lower lip in non-native clusters was not stable in native English speakers, even though English has consonant clusters. (This study was supported by KAKENHI 15K02524, 17K02707.)

Articulatory movement in consonant clusters: A contrastive study of Japanese and English

We investigated the articulation of consonant clusters with Japanese and English speakers using the WAVE system (NDI Corp.). Until now we measured the displacement of tongue tip only, but in this study we also measured the displacement of the mandible. The subjects were three Japanese and two English speakers. The speech samples were 4 words: blat, bnat, plat, pnat. All these second consonants, /l, n/ are articulated with tongue tip placed behind alveolar ridge. These words were embedded in a carrier sentence, “Say X.,” and these sentences were uttered 5 times each in random order. The articulation time from first consonants, /b/, /p/, to second consonants, /l/, /n/, were measured. Specifically, the time from the highest point of the mandible to that of the tongue tip was measured. Overall average time was 131.2 ms (Japanese) and 48.1 ms (English). Two-way ANOVA (Language vs. Cluster) showed a significant main effect in Language (p<0.0001). This result suggested that for English speakers, the first and se...

Cortical representation of processing Japanese phonemic and phonetic contrasts

This study investigated how Japanese speakers process phonemic and phonetic contrasts using voiced and devoiced vowel /u/ and /÷u/. During six oddball experiments, brain responses were measured using magnetoencephalography. Under the phonemic condition, a frequent stimulus /ch÷ita/ was contrasted with a deviant /ts÷uta/, and a frequent /ts÷uta/ with a deviant /ch÷ita/. Under the phonetic condition, a frequent /ts÷uta/ was contrasted with a deviant /tsuta/, and a frequent /tsuta/ with a deviant /ts÷uta/. Under the segment condition, vowel segments, /÷u/ and /u/, extracted from spoken words, were contrasted. The subjects were 13 native Japanese speakers. The equivalent current dipole moment (ECDM) was estimated from the mismatch field. Under the phonetic condition, the ECDM elicited by the voiced deviant was significantly larger than that elicited by the devoiced deviant in both hemispheres (p<0.01), while there were no significant deviant‐related differences in ECDM under the phonemic condition in both hem...