Breathy voice

Breathy voice (also known as murmured voice, whispery voice, or soughing) is a phonation type in which the vocal folds vibrate with reduced tension and incomplete glottal closure, allowing a relatively large volume of air to escape through the glottis, producing a characteristic noise component superimposed on the voicing.

Definition and Phonetic Description

In breathy voice, the vocal folds are held further apart than in modal (normal) voicing but are drawn sufficiently close to allow vibration. The resulting sound is perceived as “airy” or “soft,” often accompanied by audible friction. Unlike whisper, which involves no vocal fold vibration, breathy voice retains periodic vibration of the folds, albeit with a weaker harmonic structure and increased turbulent noise. The degree of breathiness can vary continuously, and many languages exploit this phonation type contrastively.

Production Mechanism

Breathy voice is produced by adjusting the laryngeal muscles so that the arytenoid cartilages are separated, leaving a posterior glottal gap through which air escapes continuously even as the vocal folds vibrate. The thyroarytenoid and interarytenoid muscles are less active than in modal voice, reducing medial compression. The vocal folds are thus longer, thinner, and less tightly adducted. The subglottal pressure remains relatively high, driving a large airflow that creates turbulence at the glottis. This aeroacoustic source combines with the periodic vibration to produce the breathy timbre.

Linguistic Occurrence

Breathy voice is found as a distinctive feature in numerous languages across the world. In Indo-Aryan languages such as Hindi, Marathi, and Gujarati, breathy-voiced consonants (often called “voiced aspirates” or “murmured stops”) contrast with plain voiceless, voiceless aspirated, and modal voiced stops. For example, Hindi distinguishes /b/ (plain voiced), /bʱ/ (breathy-voiced), /p/ (voiceless unaspirated), and /pʰ/ (voiceless aspirated). In Gujarati, the contrast extends even to vowels: certain vowels are inherently breathy while others are modal.

In East Asian languages, breathy voice appears in Wu Chinese (e.g., Shanghainese), where it characterizes a set of “slack voice” syllables, and in some dialects of Southern Min. Southeast Asian languages, such as Burmese and some Mon-Khmer languages, also use breathy phonation to distinguish lexical items. In Bantu languages like Zulu and Xhosa, breathy-voiced consonants function as “depressor consonants” that lower the pitch of adjacent tones.

Contrastive Use in Languages

Phonological contrasts involving breathy voice can be summarized as follows:

• Consonantal contrasts: The most common pattern is the opposition of modal voiced stops vs. breathy-voiced stops (e.g., Hindi /d/ vs. /dʱ/). These are often transcribed with a superscript [ʱ] or a subscript diacritic [̤].
• Vocalic contrasts: In Gujarati, vowels can be modal or breathy (e.g., /baɾ/ “hair” vs. /b̤aɾ/ “weight”).
• Tonogenesis: In languages like Chinese dialects, historical breathy voice has become a source of tonal splitting, leading to lower registers.

Perceptually, native speakers rely on both the noise component and the lower fundamental frequency (F0) often associated with breathy voice.

Perception and Acoustics

Acoustically, breathy voice is characterized by:

• Increased amplitude of the first harmonic (H1) relative to the second harmonic (H2) — a high H1–H2 difference.
• Reduced energy in higher harmonics due to the glottal damping.
• The presence of aperiodic noise, especially in the frequency range above 2–3 kHz.
• A lower spectral tilt (i.e., a steeper roll-off) compared to modal voice.
• Often a slightly lower F0, though this is not universal.

These acoustic cues allow listeners to distinguish breathy from modal voice even in the absence of other contextual information.

Notation in the International Phonetic Alphabet (IPA)

In the IPA, breathy voice is indicated by a subscript diaeresis (◌̤) placed under the symbol for the voiced segment. For example, [b̤] represents a breathy-voiced bilabial stop, and [a̤] represents a breathy-voiced vowel. Alternatively, the diacritic [ʱ] (a superscript raised glottal fricative) is used for breathy-voiced aspirated consonants (e.g., [bʱ]). The two notations are equivalent in practice, though [ʱ] is more common for stops and affricates, while [̤] is preferred for vowels and approximants.

Related Concepts

Breathy voice is one of several phonation types along a continuum of glottal aperture. It is related to:

• Modal voice: The default phonation with complete glottal closure and moderate airflow.
• Creaky voice: A phonation with very tight glottal closure, low F0, and irregular vibration.
• Whisper: A voiceless phonation with a constricted but open glottis, no periodic vibration.
• Falsetto: A high-pitched phonation produced by thin vocal folds.

Breathy voice can also be described as “murmured” or “whispery,” though phoneticians often reserve the term “murmur” specifically for the sound of breathy-voiced stops in languages like Hindi.

References

• Ladefoged, P., & Maddieson, I. (1996). The Sounds of the World’s Languages. Oxford: Blackwell.
• Laver, J. (1994). Principles of Phonetics. Cambridge: Cambridge University Press.
• Stevens, K. N. (1998). Acoustic Phonetics. Cambridge, MA: MIT Press.
• Catford, J. C. (1977). Fundamental Problems in Phonetics. Edinburgh: Edinburgh University Press.