Our goal is to find new acoustical evidences that characterize the nasality correlation by recording the month and nostril signal separately. This allows visualize the nasal and vocalic resonances individually. Few studies cover the nasal diphthongization and this phenomenon combines a partial nasalized vowel and a nasal glide. In Brazilian Portuguese (BP) the diphthong /aw/ and /ã / are distinctive. All data were recorded by Handle Separator from Glottal Enterprises. This records two acoustics output in different channels using two microphones. The plate is supported between the mouth and the nose. Six speakers from Paulistano dialect were recorded. The corpus covered back diphthongs in offset: [paw]; [saw]; [maw]; [taw]; [kaw]; [pã ]; [sã ]; [mã ]; [kã ] and [tã ]. In this task, each subject had to read the carry-sentence three times: [dʒigʊ_todʊ dʒigɐ]. Because the acoustic outputs are mixed, this method simplifies the separation between the both signal. The partial results show that the waveform and the spectrogram in this signals have a different configuration. In /ã /, the nasal waveform starts and finishes with a very-low energy. The higher energy is concentrated between the boundary of the both vocalic segments. In the spectrogram, the formants configuration are plates and they used to lose energy gradually (average: Fn1 374Hz, Fn2 2333 Hz, and Fn3 3049 Hz). This is different in oral format configuration where F2 has a descent movement and F3 has a ascend movement.