The glottis is the speech organ directly responsible for the production of voiced and voiceless sounds because it controls the opening and closing of the vocal cords (vocal folds).
How the Glottis Affects Voicing:
Voiced Sounds: The vocal cords vibrate as air passes through the glottis (e.g., /b, d, g, v, z/).
Voiceless Sounds: The vocal cords remain open, allowing air to pass freely without vibration (e.g., /p, t, k, f, s/).