Experiment 2: Coincidence of amplitude and frequency peaks in vowels

• F1 frequency and amplitude peaks occur together

• F1 frequency and amplitude have proper peaks, not at endpoints
• F1 clear and measurable, without nasalization, glottalization or aspiration
• Stable voicing source, F1 not affected by nasalization or higher formants

• Use only vowels with both peaks in middle (69954 out of 80856)
• Histograms as a function of normalized duration

• Both peaks tend to occur early in the vowel
• Frequency peaks tend to occur earlier than amplitude
• Diagonal histogram shows peaks are highly correlated
• Assumption violations increase with distance from diagonal
• Voiceless stops do not explain earliness of peaks