voiceless

Voiceless is a term in phonetics and linguistics describing a speech sound produced without vocal fold vibration. When the vocal cords do not oscillate, the sound lacks the periodic energy that characterizes voicing. In contrast, voiced sounds involve vocal fold vibration during articulation. Voicing is a contrastive feature in many languages, with pairs such as p vs b, t vs d, k vs g, f vs v, and s vs z illustrating the difference. Vowels are typically voiced, while voiceless vowels occur mainly in whisper or in languages that contrast phonation in vowels in specific contexts.

Voiceless consonants are produced with an open or non-vibrating glottis and include plosives, fricatives, and certain affricates. Common voiceless stops are p, t, and k; voiceless fricatives include f, s, ʃ, θ, and h; and voiceless affricates such as tʃ (ch) and ts in some languages. In many languages, voiceless stops can be aspirated or unaspirated, a distinction that affects the acoustic onset of the following vowel. Acoustically, voiceless sounds lack a periodic glottal source and instead show frication noise or aperiodic energy. The study of voicing helps explain phonemic inventories, historical sound changes, and the perceptual cues listeners use to distinguish similar sounds.