Auditory sensitivity to formant ratios: Toward an account of vowel normalisation

Abstract

A long-standing question in speech perception research is how do listeners extract linguistic content from a highly variable acoustic input. In the domain of vowel perception, formant ratios, or the calculation of relative bark differences between vowel formants, have been a sporadically proposed solution. We propose a novel formant ratio algorithm in which the first (F1) and second (F2) formants are compared against the third formant (F3). Results from two magnetoencephelographic (MEG) experiments are presented that suggest auditory cortex is sensitive to formant ratios. Our findings also demonstrate that the perceptual system shows heightened sensitivity to formant ratios for tokens located in more crowded regions of the vowel space. Additionally, we present statistical evidence that this algorithm eliminates speaker-dependent variation based on age and gender from vowel productions. We conclude that these results present an impetus to reconsider formant ratios as a legitimate mechanistic component in the solution to the problem of speaker normalization.

Listening to different speakers: On the time-course of perceptual compensation for vocal-tract characteristics

“…Additionally, it has also been suggested that N1 might be sensitive to the F 1 /F 3 ratio instead of absolute formant values (Monahan & Idsardi, 2010). Similar to the rationale in the current paper, that proposal was made in the light of a mechanism that helps listeners deal with between-speaker variation in formant frequencies, but then in a vowel-intrinsic manner (i.e., relying only on information within the target vowel).…”

“…Similar to the rationale in the current paper, that proposal was made in the light of a mechanism that helps listeners deal with between-speaker variation in formant frequencies, but then in a vowel-intrinsic manner (i.e., relying only on information within the target vowel). In contrast to Monahan and Idsardi (2010) and the other papers mentioned above, the current paper focused on vowel-extrinsic influences on perception, as the set of target vowels were identical across the two context conditions. In speech perception, vowel intrinsic normalization and normalization for vowel-extrinsic acoustic information probably operate in tandem (Johnson, 2005), and extrinsic normalization procedures have the potential to play a large role in overcoming betweenspeaker variation that is the result of anatomical/physiological differences between speakers .…”

Neuromagnetic evidence for a featural distinction of English consonants: Sensor- and source-space data

“…The latency and amplitude of the M100 has been shown to correlate with the fundamental frequency of tones (Roberts & Poeppel, 1996; Woods, Alain, Covarrubias, & Zaidel, 1995) and the first formant frequency of vowels (Poeppel & Marantz, 2000; Roberts, et al, 1998). Recent work suggests an additional sensitivity to vowel formants ratios in dense vowel spaces (Monahan & Idsardi, 2010). Larger ratios between the first and third vowel formant (F1/F3) elicited earlier M100 latencies.…”

Caractéristiques acoustiques des voyelles fermées tendues, relâchées et allongées en français québécois /

“…• l'échelle des equivalent rectangular bandwidth-rate (ou ERB-rate), proposée par Peterson, 1951;Monahan et Idsardi, 2010). Comme l'illustre la Figure On peut également calculer la distance, sur une échelle tonotopique, telle que celle des barks, entre deux formants ou entre un formant et la Fo.…”