Table of vowels

The table of vowels is a fundamental diagrammatic tool in phonetics, representing the articulation of vowel sounds within the International Phonetic Alphabet (IPA) through a standardized chart that maps tongue position and lip configuration.^[1] This chart, often depicted as a trapezoid or quadrilateral, categorizes vowels primarily by their height—ranging from close (high tongue position) to open (low tongue position)—and by backness, dividing them into front, central, and back categories.^[2] The vertical axis of the chart corresponds to vowel height, with four primary levels: close, close-mid, open-mid, and open, reflecting the degree to which the tongue is raised toward the roof of the mouth during production.^[1] Horizontally, it distinguishes tongue advancement, positioning front vowels (tongue forward, as in ) on the left, central vowels (neutral, as in [ə]) in the middle, and back vowels (tongue retracted, as in ) on the right.^[2] Where relevant, symbols appear in pairs to indicate rounding: unrounded vowels (lips spread or neutral) on the left and rounded vowels (lips pursed) on the right, such as (unrounded) paired with (rounded).^[1] Developed as part of the IPA system established by the International Phonetic Association in 1886, the vowel table provides a universal framework for transcribing and comparing vowel inventories across languages, aiding linguists in documenting phonetic variations without reliance on orthographic ambiguities. It includes 28 principal symbols for monophthongs, though not all are used in every language, and excludes diphthongs or suprasegmental features, which are represented separately.^[2] The chart's design draws from acoustic and articulatory principles, with symbols like , , , , and historically aligned with vowel qualities in Romance languages for intuitive reference.^[3]

Overview

Definition and Components

A vowel table, also known as a vowel chart, is a schematic diagram used in phonetics to visually represent vowel sounds by plotting them according to key articulatory features, primarily the position of the tongue in the vocal tract.^[4][5] This representation categorizes vowels along two primary axes: tongue height, which ranges from close (highest tongue position) to open (lowest tongue position), including intermediate levels such as near-close, close-mid, open-mid, and near-open; and tongue backness, which spans from front to back, with a central position in between.^[5] The chart's trapezoidal shape approximates the configuration of the oral cavity, with the vertical axis corresponding to height and the horizontal axis to backness, providing a standardized framework for comparing vowels across languages.^[4][5] Core components of a vowel table include symbols from the International Phonetic Alphabet (IPA), the globally recognized system for phonetic notation.^[4] These symbols denote specific vowel qualities, such as for the close front unrounded vowel, for the open front unrounded vowel, and for the close back rounded vowel.^[5] A key distinction within the chart is between rounded and unrounded vowels, where lip protrusion affects the sound; for instance, represents the close front rounded counterpart to the unrounded .^[4][5] The IPA briefly references this structure in its cardinal vowel system to anchor relative positions, though full details appear in dedicated phonetic resources.^[4] To illustrate the basic layout, consider a simplified excerpt focusing on front unrounded vowels, arranged by tongue height from close to open: This grid-like organization within the trapezoid highlights how vowel symbols are positioned to reflect articulatory parameters, facilitating precise phonetic analysis.^[5]

Historical Context and Evolution

The classification of vowels based on articulatory features, particularly tongue position, emerged in the early 19th century through the work of linguists such as Alexander John Ellis. In publications like Essentials of Phonetics (1848) and On Early English Pronunciation (1869–1889), Ellis pioneered graphical representations of vowels, plotting them on diagrams that approximated tongue height and frontness or backness within the oral cavity. These early vowel charts, often trapezoidal in form, shifted phonetic description from purely auditory impressions to systematic articulatory models, influencing subsequent European phonetic traditions.^[6][7] The formalization of vowel tables advanced with the establishment of the International Phonetic Association (IPA) in 1886, which sought to create a universal system for phonetic transcription. By the late 19th century, the IPA began standardizing vowel symbols and arranging them in charts based on tongue position, drawing on Ellis's foundational ideas and earlier systems like the Romic alphabet. The first comprehensive IPA chart appeared in 1900, introducing symbols such as [ə] for the mid-central vowel and organizing vowels by height levels (close, half-close, half-open, open) along a sagittal view of the vocal tract.^[8][9] Subsequent revisions refined the vowel chart to better reflect linguistic diversity. The 1947 update, published in Le Maître Phonétique, included additions such as r-coloured vowels (e.g., [eɹ]) and lowered variants (e.g., [ɩ], [ɷ]), along with revisions to other symbols like the glottal stop [ʔ]. The 1989 Kiel Convention, a pivotal meeting of the IPA, revised the overall chart principles to emphasize phonetic categories over historical orthography, enhancing clarity in vowel notation, standardizing diacritics, and improving layout for international use without major new symbol additions. A 1993 revision further expanded the central vowel series by resurrecting symbols for mid-central vowels, including [ɘ] (mid central unrounded), [ɵ] (mid central rounded), [ɜ] (open-mid central unrounded), and [ɞ] (open-mid central rounded), addressing previous gaps in representing these positions. Further updates in 2020 incorporated minor adjustments to symbols and chart design, ensuring compatibility with digital tools and ongoing acoustic research.^[8][10] Throughout the 20th century, vowel tables evolved from subjective auditory classifications to integrations of empirical articulatory and acoustic data. Techniques such as X-ray cinematography in the 1920s–1930s and spectrographic analysis post-World War II allowed for precise validation of tongue positions and formant frequencies, leading to refinements in chart accuracy and the inclusion of data-driven symbols. This shift, exemplified by Daniel Jones's Cardinal Vowel system (1917), grounded modern IPA vowel representations in measurable phonetic properties rather than impressionistic sketches.^[6][9]

Articulatory Basis

Tongue Position and Height

Vowels are primarily classified articulatorily by the position of the tongue within the oral cavity, which shapes the vocal tract without any constriction sufficient to produce consonant-like friction or stoppage. This positioning determines the quality of the vowel sound, with the tongue's elevation and horizontal placement serving as the two main dimensions in phonetic tables. Unlike consonants, which involve targeted airflow obstruction, vowels rely on the overall configuration of the tongue body to modulate resonance, allowing for a continuum of sounds based on subtle variations in height and backness.^[11][12] Tongue height, also known as vowel height, refers to the vertical position of the tongue relative to the roof of the mouth, often correlated with the degree of jaw opening. High or close vowels, such as as in "beat," involve the tongue raised closest to the hard palate, with minimal jaw depression to create a relatively small oral cavity opening. Mid vowels occupy an intermediate position: close-mid vowels like in "bait" feature the tongue somewhat elevated with moderate jaw lowering, while open-mid vowels such as [ɛ] in "bet" have the tongue lower and the jaw more open. Low or open vowels, exemplified by or [ɑ] as in "father," position the tongue at its lowest point, maximizing jaw opening and resulting in the largest oral cavity space. These height distinctions provide a foundational vertical axis for organizing vowels in phonetic charts.^[12][13][11] Tongue backness describes the horizontal advancement or retraction of the tongue along the midline of the mouth, influencing the anterior-posterior shaping of the vocal tract. Front vowels, like in "beat" or [æ] in "bat," are produced with the tongue body pushed forward toward the hard palate, narrowing the front cavity while expanding the back. Central vowels maintain a neutral tongue position in the middle of the mouth, as in [ə] the schwa sound common in unstressed syllables, creating a balanced resonance space. Back vowels, such as in "boot" or [ɑ] in "cot," involve the tongue retracted toward the soft palate or velum, which enlarges the front cavity and constricts the pharyngeal area. This backness spectrum forms the horizontal axis in vowel tables, allowing systematic plotting of sounds based on their articulatory coordinates.^[12][11][13] In standard vowel diagrams, these dimensions intersect to position symbols intuitively: high-front vowels like appear at the top-left, low-back vowels like [ɑ] at the bottom-right, and central-mid vowels like [ə] near the center, reflecting the tongue's dual movements during articulation. Lip rounding serves as a secondary modifier to these primary tongue positions but is not central to height or backness classification.^[12][11]

Lip Rounding and Other Features

Lip rounding constitutes a key secondary articulatory feature in vowel production, distinguishing unrounded vowels, produced with spread or neutral lips (e.g., the high front unrounded as in English "see"), from rounded vowels, articulated with pursed or protruded lips (e.g., the high back rounded as in "boot" or the high front rounded as in French "tu").^[14][4] This rounding narrows the front vocal tract cavity, effectively lengthening it and lowering the second formant frequency (F2), which contributes to the distinct perceptual quality of rounded vowels compared to their unrounded counterparts.^[15][16] In many languages, lip rounding correlates with tongue backness, but it can occur independently, as in front rounded vowels like or [ø].^[17] Beyond basic tongue positioning, vowels exhibit other modifying features that influence their realization and transcription in phonetic tables. Vowel length, a durational distinction, is represented in the International Phonetic Alphabet (IPA) using the diacritic ː to mark prolonged vowels (e.g., long [iː] versus short [ɪ]), affecting phonetic contrasts in languages like German or Finnish where length is phonemic.^[4] Tension, or muscular effort in the vocal tract, differentiates tense vowels (e.g., , with greater articulatory precision) from lax vowels (e.g., [ɪ], with more relaxation), often conveyed through distinct IPA symbols rather than diacritics, as seen in English high vowels.^[14] Rhoticity, an r-coloring from retroflexion or bunching of the tongue, appears in some dialects (e.g., North American English [ɚ] in "butter"), transcribed with the diacritic ˞ or dedicated symbols like [ɚ].^[4] Labialization, a related protrusion, may use the superscript ʷ (e.g., [iʷ]), though it overlaps with rounding in vowel contexts.^[4] In standard IPA vowel charts, these features are integrated without separate dimensions; rounded vowels are typically offset to the right, with the back row assuming default rounding (e.g., [u, o, ɔ]), while unrounded variants require explicit symbols or diacritics like the umlaut ¨ for front rounding adjustments.^[4] This tabular representation prioritizes height and backness as primary axes, appending secondary traits via modifiers to capture nuances efficiently.^[18] Such features create phonemic contrasts in various languages; for instance, lip rounding distinguishes the French unrounded high front vowel in "si" (if) from the rounded in "tu" (you), highlighting how rounding alters vowel identity without changing tongue height.^[19][20] These modifications enhance the precision of vowel tables, allowing phoneticians to denote subtle articulatory and acoustic variations essential for linguistic analysis.^[4]

Standard IPA Vowel Chart

Monophthongs by Position

Monophthongs in the International Phonetic Alphabet (IPA) are steady-state vowels characterized by a single, unchanging tongue position and quality during articulation. They are systematically arranged on the IPA vowel chart, a trapezoidal diagram representing the vowel space based on two primary articulatory parameters: tongue height (from close/high to open/low) and tongue backness (from front to central to back). The chart divides the space into seven heights—close, near-close, close-mid, mid, open-mid, near-open, and open—and three backness positions, with additional distinctions for lip rounding (unrounded symbols typically on the left, rounded on the right within each cell). This 7-by-3 grid accommodates over 28 symbols, including variants, to capture the full range of possible monophthong qualities across languages. The standard chart is from the 2015 IPA revision, with no changes as of 2025.^[21][22][4] Front monophthongs involve advancement of the tongue toward the front of the oral cavity, often with spread or neutral lips to facilitate the higher and fronter positions. The close front unrounded vowel features the tongue raised high and pushed forward, nearly touching the hard palate, with lips spread as in "see" (English approximation). The close-mid front unrounded lowers the tongue slightly while maintaining frontness, as in "say" (English). Further descent yields the open-mid front unrounded [ɛ], with the tongue in a mid-low front position, lips unrounded, similar to "bed" (English). At the near-open front level, [æ] positions the tongue low and front, with a wide-open jaw and spread lips, as in "cat" (English). The open front unrounded is even lower. Rounded front variants, such as (close) and [ø] (close-mid), add lip protrusion while preserving the front tongue position.^[21][11] Central monophthongs exhibit a neutral tongue position, neither strongly advanced nor retracted, reflecting a balanced placement in the mouth's midline. The close central unrounded [ɨ] raises the tongue high but centrally, with neutral lips, occurring in languages like some Indigenous American tongues. The mid central unrounded [ə], known as schwa, holds the tongue at mid-height centrally, often unstressed and with relaxed lips, as in the first syllable of "about" (English). The open-mid central unrounded [ɜ] lowers the tongue to a mid-low central spot, unrounded, similar to the vowel in "bird" (some English dialects). For near-open central, [ɐ] places the tongue low and central, with neutral lips, as in many non-rhotic English realizations of "father." Central rounded counterparts, like [ʉ] (close) and [ɵ] (mid), incorporate lip rounding to the neutral tongue base. The open-mid central rounded [ɞ] adds rounding at that height.^[21][11] Back monophthongs retract the tongue toward the soft palate (velum), typically with lip rounding for higher positions to aid the posterior placement, though lower back vowels are often unrounded. The close back unrounded [ɯ] elevates the tongue high and back without rounding, as in Japanese "u" approximations, while the rounded adds pursed lips for the high back position, as in "boot" (English). At close-mid height, unrounded [ɤ] retracts the tongue mid-high without rounding, and rounded protrudes the lips, akin to "go" (English). The open-mid back unrounded [ʌ] lowers to mid-low backness, unrounded, as in "cup" (English), with rounded counterpart [ɔ] featuring lip rounding, like "thought" (English). The open back unrounded [ɑ] drops the tongue low and far back, jaw open, lips neutral, as in "father" (English). Lip rounding is a default for many back vowels but varies by language. The open back rounded [ɒ] adds rounding at the lowest back position.^[21][11] The standard IPA monophthong chart can be represented textually as follows, showing the 7-height grid with primary symbols (unrounded left, rounded right where applicable; additional diacritics for near-positions like ɪ, ʊ are variants but included for completeness): This grid illustrates the abstract vowel space, where actual realizations may deviate slightly due to coarticulation or language-specific phonetics, but it serves as the foundational reference for transcription.^[21][22][4]

Diphthongs and Complex Vowels

Diphthongs are vowel sounds that involve a glide from one vowel quality to another within a single syllable, transcribed in the International Phonetic Alphabet (IPA) as sequences of two symbols, such as [aɪ] for the diphthong in the English word "my". Falling diphthongs start with a more prominent nucleus vowel and transition to a less prominent offglide, often toward a close approximant, as in [aɪ] (English "my") and [aʊ] (English "now"). In contrast, rising diphthongs start with a less prominent onglide (close glide like or ) and end with a more prominent nucleus vowel, such as [ja] in Spanish "ya" (meaning "already").^[19][23] Complex vowels extend beyond simple diphthongs to include triphthongs, which combine three vowel qualities in one syllable, transcribed as sequences like [aɪə] in English "fire". R-colored vowels, also known as rhotic vowels, incorporate an r-like quality and are notated using symbols such as [ɚ] for the mid-central r-colored schwa (as in American English "butter") or diacritics like [ɑɹ˔] to indicate retroflex approximation. Nasalized vowels are marked with a tilde diacritic above the vowel symbol, such as [ã] for a nasalized open front unrounded vowel, resulting from co-articulation with a following nasal consonant.^{[24][25][26][27]} In extensions to the standard IPA vowel chart, diphthongs are represented on auxiliary diagrams by arrows connecting the positions of their endpoint monophthongs, illustrating the trajectory from onset to offset vowel qualities. IPA conventions for co-articulated vowels, including non-pulmonic influences or additional features like rhoticity and nasalization, employ diacritics placed above or below the base vowel symbol to denote these modifications without altering the core chart.^{[28][29][4][30]} Acoustically, diphthongs differ from monophthongs by exhibiting dynamic formant trajectories, where formants—particularly the second formant (F2)—shift in frequency from the onset to the offset vowel, creating a gliding effect, whereas monophthongs maintain a relatively steady-state formant structure.^[31][32]

Applications and Variations

Use in Phonetic Transcription

Vowel tables, such as the standard IPA chart, play a crucial role in phonetic transcription by providing a visual and systematic reference for selecting appropriate symbols to represent vowel sounds with varying degrees of precision. In broad transcription, which focuses on phonemic distinctions relevant to a specific language, the table allows transcribers to choose general symbols like /ɪ/ for the lax high front vowel in English words such as "bit," emphasizing contrasts that affect meaning without capturing fine phonetic details.^[33] In contrast, narrow transcription uses the table to incorporate more exact allophonic variations, such as [ɪ̈] with a centralizing diacritic for subtle deviations in actual pronunciation, enabling detailed analysis of speaker-specific realizations.^[34] Practical guidelines for using vowel tables in transcription involve matching auditory perceptions of vowel quality to positions on the chart, where tongue height and backness guide symbol selection, often supplemented by acoustic tools for verification. Transcribers associate heard vowels with chart coordinates—for instance, a mid-central vowel might align with [ə]—and use spectrograms to confirm placements by measuring formant frequencies, such as lower F1 values indicating higher tongue position.^[35] This acoustic validation ensures transcriptions reflect measurable phonetic properties rather than subjective impressions alone.^[36] In applications to dictionaries and linguistic corpora, standardized vowel tables promote consistency in documenting pronunciations across resources, as seen in the Oxford English Dictionary's use of IPA symbols derived from the chart to represent British and American English vowels uniformly.^[37] Similarly, corpora like those compiled by the International Phonetic Association rely on the table to maintain reproducible transcriptions in large-scale speech databases, facilitating comparative phonetic studies.^[38] Challenges in using vowel tables for transcription arise from dialectal variations, which may shift vowel realizations beyond standard chart positions, necessitating diacritics or extensions to capture regional differences while preserving the IPA as a universal framework. For example, mergers like the cot-caught distinction in some North American dialects require adjusted symbols, yet the table's foundational structure ensures cross-dialect comparability.^[39] The IPA symbols referenced in these practices, such as those for monophthongs, provide the core notation system.^[36]

Adaptations in Specific Languages

In English, vowel tables are adapted to represent a subset of 12 to 14 monophthongs and 5 to 8 diphthongs, depending on the dialect, rather than the full IPA grid; for instance, General American (GA) includes the low front unrounded [æ] as in "cat" and the diphthong [aʊ] as in "cow," while Received Pronunciation (RP) distinguishes additional qualities like the near-open back rounded [ɒ] absent in GA due to the father-bother merger.^[40][41] These adaptations highlight dialectal contrasts, with GA favoring a rhotic-influenced system that reduces certain back vowel distinctions compared to RP's more fronted realizations.^[40] French phonology customizes vowel tables by incorporating four nasal vowels—[ɛ̃], [ɑ̃], [ɔ̃], and [œ̃]—which are produced with velum lowering and occupy positions outside the standard oral monophthong chart, as in "vin" [vɛ̃] or "bon" [bɔ̃].^[42] These nasals require dedicated cells in adapted charts, reflecting French's contrast between oral and nasal series, with [ɛ̃] serving as a prototypical open-mid front nasal.^[42] Such modifications ensure tables capture phonemic distinctions unique to Romance languages, avoiding overlap with oral vowels like [ɛ] or [ɔ].^[43] Mandarin Chinese adapts vowel tables to a compact inventory of about 6 to 9 monophthongs, such as , , , and [ɤ], where tones fundamentally alter perception and realization; for example, the high front in a high-level tone (mā) contrasts acoustically with its low-falling counterpart (mà), often notated with diacritics like ˥ or ˥˩ on the vowel symbols.^[44] These tone-vowel interactions lead to reduced charts emphasizing syllabic structure over full height-rounding variation, as Mandarin includes the high front rounded but lacks mid front rounded vowels like [ø].^[45] Turkish vowel harmony principles adapt the IPA chart by restricting sequences to either front ([e, i, ø, y]) or back ([a, ɯ, o, u]) vowels within words, filling only symmetric portions of the grid without mid-central or front-back mixes; for instance, suffixes harmonize with roots, as in "ev-ler" [evleɾ] (front) versus "kol-lar" [kollaɾ] (back).^[46] This system, a hallmark of Altaic languages, results in an eight-vowel inventory that prioritizes harmony features over independent height or rounding, omitting rare positions like high front rounded vowels in non-harmonic contexts.^[46] For computational and orthographic applications, systems like SAMPA adapt IPA vowel symbols into ASCII-compatible forms, such as "E" for [ɛ], "A:" for [ɑː], or "9" for [œ], enabling machine-readable transcriptions without special characters while preserving distinctions like English's tense-lax pairs.^[47] In documenting endangered languages, vowel tables are extended to include rare phonemes, such as the close central rounded [ʉ̜] in some Australian Aboriginal languages like Dalabon, which fall outside standard IPA cells and require precise acoustic verification for preservation efforts.^[48] The following table illustrates how select languages populate subsets of the IPA vowel space: