The Human Speech System
Learning Outcomes
By the end of this chapter, you will be able to:
- Identify the major structures involved in producing speech.
- Distinguish the active and passive articulators.
- Trace the path of pulmonic airflow from the lungs to its release through the mouth or nose.
- Explain the roles of the larynx, velum, tongue, lips, and jaw in shaping speech.
- Interpret a labeled sagittal diagram of the vocal tract.
- Perform safe, simple self-observation of your own articulation.
Opening Question
You have one mouth and one throat, yet you can produce thousands of distinct speech sounds, often without thinking about how you do it. A trumpet player has to learn every valve combination deliberately. You learned to coordinate dozens of muscles in your lungs, throat, and mouth before you could read or write — and you did it almost entirely by listening and imitating.
This chapter asks a simple question: what is actually happening inside your body when you speak? Before this course studies individual sounds, you need a working map of the system that produces all of them.
- Without looking in a mirror, try to describe what your tongue is doing right now, at rest. Most people find this surprisingly hard — we rarely pay attention to articulators we cannot see.
- Say the word "speech" slowly. Can you feel any single moment where your mouth is completely still? You will return to this observation later in the chapter.
The Speech Production Chain
Phonetics divides the study of speech into three branches: articulatory phonetics, which examines how the body produces speech; acoustic phonetics, which examines the sound waves that result; and auditory phonetics, which examines how listeners perceive those sound waves. This chapter focuses on the first branch. Later chapters return to acoustic and auditory evidence once you have a physical map to connect it to.
Speech production can be described as a chain of physical events. Each stage depends on the one before it:
- Air is pushed outward from the lungs.
- The air travels up the trachea, or windpipe.
- The air reaches the larynx, where the vocal folds may be set into vibration.
- The air continues into the vocal tract — the pharynx, and then the oral or nasal cavity.
- The tongue, lips, jaw, and other articulators shape the airflow into a particular sound.
- The shaped sound exits through the mouth, the nose, or both at once.
This chain is sometimes called the respiratory, phonatory, and articulatory system, corresponding to three broad regions of the body: the lungs and airway, the larynx, and everything above it. The next three sections take up each region in turn.
A note on language: this chapter describes anatomy and physiology that every human speaker shares, regardless of which language or languages they speak. The specific sounds a language uses, and how that language organizes them, are the subject of later chapters.
The Respiratory System
Purpose: understand how breathing supplies the airflow that speech requires.
Ordinary breathing and speech breathing are not identical. When you breathe quietly at rest, you inhale and exhale in roughly equal amounts of time. When you speak, you typically take a quicker inhalation and then release the air slowly and under careful muscular control while you talk. The diaphragm, a dome-shaped muscle beneath the lungs, and the muscles of the rib cage work together to manage this controlled release.
Almost all speech sounds in the world's languages are produced on an egressive airstream — air moving outward from the lungs. Phoneticians call this the pulmonic egressive airstream mechanism, because it originates in the lungs (pulmonic) and moves outward (egressive).
Not every speech sound uses lung air. A smaller number of the world's languages also use airstreams generated elsewhere in the vocal tract — for example, sounds produced with air trapped and released in the mouth, or air drawn inward rather than pushed outward. This chapter previews that fact without naming or classifying those sounds; Chapter 13 returns to non-pulmonic airstream mechanisms in detail, once you have the place and manner vocabulary to describe them precisely.
Controlled exhalation matters because fluent speech requires a steady, manageable supply of air across an entire phrase, not just a single sound. Running out of breath mid-phrase, or releasing air too quickly, disrupts the rhythm and clarity of speech — one reason breath management is a frequent topic in voice training and public speaking, even though it rarely comes up in everyday conversation about language.
Try It: Feeling Controlled Exhalation
Place a hand flat on your stomach, just below your ribs. Take a normal breath and let it out silently — notice the movement. Now take a breath and count aloud from one to ten at a steady pace. Notice how much more slowly and deliberately the air leaves your body compared with silent breathing. This is the same controlled airflow that powers every sound you will study in this course.
The Larynx and Phonation
Purpose: understand how the larynx turns moving air into voiced sound.
Once air leaves the trachea, it passes through the larynx, a structure made of cartilage and muscle that most people can feel at the front of the throat. Stretched across the larynx are the vocal folds — two small bands of muscle and tissue, sometimes informally called "vocal cords." The space between the vocal folds is called the glottis.
The vocal folds can be positioned in different ways:
- When the vocal folds are held apart, air passes through the glottis freely. No vibration occurs. This is the setting for voiceless sounds, and for ordinary breathing. Example: the first sound in "see" is voiceless.
- When the vocal folds are drawn close together, the moving air causes them to vibrate rapidly, opening and closing many times per second. This is the setting for voiced sounds. Example: the first sound in "zoo" is voiced.
This rapid vibration is sometimes compared to a reed instrument, where a thin, flexible material vibrates as air is forced past it, or to a pair of stretched rubber bands fluttering in a breeze. Both comparisons capture something real — vibration caused by moving air — but the vocal folds are living tissue under fine muscular control, not a fixed mechanical reed, so the comparison should not be pushed too far.
Try It: Feeling Voicing
Place two fingers lightly on the front of your throat, over the larynx. Say a long, sustained "zzzzz" sound, then switch to a long "ssssss" sound, alternating a few times. You should feel a buzzing vibration during "zzzzz" that disappears during "ssssss." The two sounds are produced with the tongue and teeth in the same position; the only difference is whether the vocal folds are vibrating.
Misconception: The vocal folds vibrate for every sound you make, since you are constantly producing audible speech.
Correction: Many sounds in spoken language are voiceless — produced with the vocal folds held apart and not vibrating. The "Try It" activity above demonstrates this directly: "sssss" is fully audible, but the vocal folds are not vibrating during it.
The Vocal Tract
Purpose: understand the resonating space above the larynx and how its shape affects sound.
Everything above the larynx is sometimes referred to together as the vocal tract: the pharynx (the tube-like space behind the tongue and above the larynx), the oral cavity (the mouth), and the nasal cavity (the space behind the nose). Air that leaves the larynx, voiced or voiceless, passes through some combination of these spaces before it reaches the outside air.
The vocal tract acts as a resonating chamber. Its size and shape change constantly as you speak, because the tongue, lips, jaw, and velum are all capable of movement. Each distinct shape of the vocal tract changes the quality of the sound that passes through it, in much the same way that changing the shape of a wind instrument's tubing changes its pitch and timbre. Unlike most instruments, however, the vocal tract can reshape itself many times per second during continuous speech.
This constant reshaping is the basic physical fact behind everything you will study in the chapters ahead. Differences between speech sounds are, at the most basic level, differences in how the vocal tract is shaped at a given moment.
Active and Passive Articulators
Purpose: identify the structures that shape the vocal tract and distinguish which ones move toward which.
The structures that shape the vocal tract are called articulators. Phoneticians find it useful to distinguish two kinds:
- Active articulators move toward another structure to create a constriction. The lower lip and the tongue are the body's main active articulators — the tongue especially so, since different parts of it can move independently.
- Passive articulators are typically the target of that movement, and do not move much themselves. The upper lip, the upper teeth, and the roof of the mouth are largely passive in this sense.
This is not a rigid division — the lower jaw, for example, supports the movement of the lower lip and tongue without itself being usually classified as either fully active or passive — but the active/passive distinction is useful shorthand that you will see again when later chapters classify consonants by place of articulation.
| Structure | General role | Brief description |
|---|---|---|
| Tongue | Primarily active | The most mobile articulator; commonly divided into the tip, blade, front, back, and root. |
| Lower lip | Primarily active | Moves to contact the upper lip or upper teeth. |
| Upper lip | Primarily passive | A common target for the lower lip. |
| Upper teeth | Primarily passive | A common target for the tongue or lower lip. |
| Alveolar ridge | Primarily passive | The small ridge directly behind the upper front teeth. |
| Hard palate | Primarily passive | The bony, domed roof of the mouth behind the alveolar ridge. |
| Soft palate (velum) | Active | The muscular rear portion of the roof of the mouth; raises and lowers to direct airflow. |
| Uvula | Passive or active, depending on the sound | The small fleshy structure hanging from the rear of the velum. |
| Lower jaw | Supports active articulators | Adjusts the overall opening of the mouth and the position of the lower lip and tongue. |
Try It: Locating the Alveolar Ridge
Place the tip of your tongue just behind your upper front teeth, then slide it slowly backward along the roof of your mouth. You should feel a small bump or ridge a short distance back — this is the alveolar ridge. Continue further back and notice where the hard, bony roof of your mouth gives way to soft tissue; this transition marks the start of the soft palate, or velum.
This chapter introduces these structures by name and function only. Later chapters classify entire consonant systems using the place-of-articulation terms previewed in this table — that detailed work begins once Chapter 7 takes up places of articulation directly.
A Closer Look at the Tongue
Because the tongue is involved in producing more speech sounds than any other articulator, it is useful to have vocabulary for its different regions. From front to back, phoneticians commonly distinguish the tip, the blade, the front, the back, and the root of the tongue.
These regions are not separated by any visible boundary — the tongue is a single, highly flexible muscular organ — but distinguishing them lets phoneticians describe, for example, that one sound is made with the tongue tip and another with the tongue back, even though both are "the tongue."
This versatility is also why the tongue is frequently involved in articulation difficulty when learning an unfamiliar language: a speaker's tongue has developed precise habitual movements for the sounds of languages they already know, and producing an unfamiliar sound often means learning a tongue position or movement that feels unfamiliar at first. Chapter 1 introduced the idea that this is a matter of unfamiliar coordination, not a personal or biological limitation.
Oral and Nasal Airflow
Purpose: understand how the velum directs air through the mouth, the nose, or both.
Air leaving the pharynx can exit through the oral cavity, the nasal cavity, or both at once. Which path it takes depends on the position of the velum, the soft, muscular rear portion of the roof of the mouth.
- When the velum is raised, it presses against the back wall of the pharynx and seals off the nasal cavity. Air can only exit through the mouth. This is the setting for oral sounds.
- When the velum is lowered, air can pass into the nasal cavity and exit through the nose. This is the setting for nasal sounds and ordinary nasal breathing.
This chapter introduces velum position only as a general mechanism. A detailed account of nasal consonants, including how they are classified by place of articulation, belongs to Chapter 11.
Try It: Oral Versus Nasal Airflow
Hold a small mirror, or simply the back of your hand, just under your nostrils. Say a long "mmmmm" sound and notice airflow against your skin or fogging on the mirror. Now say a long "zzzzz" sound, keeping your mouth in roughly the same position, and notice that the airflow under your nose disappears. For "mmmmm," the velum is lowered and air escapes through the nose; for "zzzzz," the velum is raised and air escapes only through the mouth.
Coordination, and Why This System Is Shared Across Languages
Producing fluent speech requires dozens of muscles in the lungs, larynx, tongue, lips, jaw, and velum to move in close coordination, often changing position several times per second. Most of this coordination happens automatically once a pattern is well learned — which is exactly why describing your own tongue position at rest, as the opening question of this chapter asked, can feel surprisingly difficult. Skills that are highly automatic are often the hardest to observe consciously.
Every spoken human language uses this same basic biological system: lungs, larynx, and vocal tract. No language and no accent relies on different anatomy, and no speaker's speech organs are better or worse suited to language in general. What differs between languages — and the subject of the rest of this course — is how each language organizes and uses this shared system: which constrictions it treats as meaningfully different from one another, and which contrasts it ignores. A speaker who finds an unfamiliar sound difficult to produce is encountering unfamiliar muscular coordination, not a deficiency of any kind.
Later chapters will examine how individual languages select and organize places and manners of articulation from this same shared anatomical inventory, building toward a method you can apply to any language you choose to study.
Key Terms
| Term | Definition |
|---|---|
| Articulatory phonetics | The study of how the body produces speech sounds. |
| Respiratory system | The lungs, diaphragm, and airway that supply moving air for speech. |
| Pulmonic egressive airstream | An outward-moving airstream originating in the lungs; the airstream mechanism used by most speech sounds. |
| Larynx | The structure in the throat containing the vocal folds. |
| Vocal folds | Two bands of tissue in the larynx that can vibrate to produce voicing. |
| Glottis | The space between the vocal folds. |
| Voiced / voiceless | Describing whether the vocal folds are vibrating (voiced) or held apart (voiceless) during a sound. |
| Vocal tract | The pharynx, oral cavity, and nasal cavity, considered together as a resonating space above the larynx. |
| Pharynx | The tube-like space behind the tongue and above the larynx. |
| Oral cavity | The mouth, considered as a resonating space. |
| Nasal cavity | The space behind the nose, considered as a resonating space. |
| Articulator | Any structure involved in shaping the vocal tract during speech. |
| Active articulator | An articulator that moves toward another structure to form a constriction. |
| Passive articulator | An articulator that is typically the target of an active articulator's movement. |
| Velum (soft palate) | The muscular rear portion of the roof of the mouth, which raises or lowers to direct air into or away from the nasal cavity. |
| Alveolar ridge | The small ridge of gum tissue directly behind the upper front teeth. |
| Hard palate | The bony, domed front portion of the roof of the mouth. |
| Uvula | The small fleshy structure hanging from the rear of the velum. |
Chapter Review
Part A — Identification
1. Name the three broad systems involved in producing speech.
2. What is the difference between an active and a passive articulator? Give one example of each.
3. What structure separates oral sounds from nasal sounds, and how does it do this?
Part B — Label the Diagram
1. Using the sagittal diagram from this chapter (Figure CH04_FIG_01), label the following structures: lungs, trachea, larynx, pharynx, oral cavity, nasal cavity, tongue, and velum.
Part C — Explanation
1. Trace the complete pathway of air from the lungs to the release of a voiced oral sound, naming every major structure the air passes through and stating what each structure does.
2. Explain, in your own words, why "the vocal folds always vibrate during speech" is an inaccurate statement.
Repaso acumulativo / Cumulative Review
1. Chapter 1 distinguished observation, inference, and judgment. Choose one "Try It" activity from this chapter and write one sentence that is a pure observation and one sentence that would count as an inference.
Practical Task
Practical Performance Task
Mapping Your Own Speech System
Working independently or with a partner, complete the following self-observation log:
- For each of the three "Try It" activities in this chapter, write one or two sentences describing what you actually felt or observed.
- Choose three articulators from the Key Terms table and identify, by touch or sight where possible, where each one is located in your own mouth or throat.
- Describe, in your own words and without naming any specific consonant or vowel, the complete pathway air takes when you say a sustained, voiced, oral sound such as a long "ahh."
This task asks you to connect anatomical vocabulary to your own direct physical experience — the same connection you will rely on throughout the rest of this course.
Looking Ahead
What You Now Know
You can now describe, in plain language, how breathing, the larynx, and the vocal tract work together to produce speech, and you can locate the body's major articulators by touch. This shared biological system underlies every sound in every spoken language, and it is the foundation the rest of this course builds on.