Oddly enough, it's been my observation that in きゃ and ぎゃ, the /a/ sound is considerably fronted compared to other syllables. It's usually realized as the centra

Oddly enough, it's been my observation that in きゃ and ぎゃ, the /a/ sound is considerably fronted compared to other syllables. It's usually realized as the central vowel [ä], but in these two, it's often fronted to [a]. This is why these syllables are used to render English words containing /kæ/ into Japanese, such as "cannon" (キャノン kyanon) or "cat" (キャット kyatto). Contrast with "cut" (カット katto) or "car" (カー kā). Japanese has some interesting allophones. I also find the allophones in the Z-row fascinating as well ([z] and [d͡z] are allophones in free variation).