調べてみたけど、やっぱり声門閉鎖音は他の閉鎖音とは異なりフォルマント遷移が起こらないよ。
Acoustics of American English Speech
"Because glottal stops are formed at the glottis, the position or the motion of the articulators is not affected.
Therefore, there is no particular formant structure or formant motion associated with these phenomena."
Glottal Stop in Vero South Estonian (エストニア語についてだけど)
"an acoustic characteristic of the glottal stop is the stability of the formants in the preceding vowel,
which is natural because in the case of the laryngeal stop the closure is formed not in the oral cavitybut in the larynx.
Differently from other stops, the beginning and end values of F1, F2 and F3 of the vowel preceding the glottal stop are
virtually the same."
