Thanks so much. I speak French and I realized that the difference btw Ka & Ga is voiced and voiceless instead of aspiated or not but most of my Japanese teachers seems unaware of this rule and they sometimes forced to pronounced K as aspirated.
目前關東及東北地區的母語者,在發語頭的有聲子音時,有+VOT化(即有聲子音若置於語頭位置可能不會震動)的現象,而語頭的無聲子音皆會送氣,導致許多學習者認為「清音=送氣」,「濁音=不送氣」。不過若將有聲子音置於語中位置,大多還是呈現有聲;而無聲子音置於語中位置時,依然是呈現無聲,但大多數是不送氣的。 總而言之,若是在語頭位置,的確可以藉由是否送氣判斷,然而於語中位置,依然需要確認該子音在母音發生前聲帶是否震動。 Thanks so much for your explanation. This is also my observation.