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Look up words and phonemes, compare phoneme features, or search by distinctive features.

Overview

The Lookup tool provides four modes: 1. Word Lookup - Complete phonological and psycholinguistic profile for any word 2. Phoneme Lookup - View all 38 articulatory features for any phoneme 3. Phoneme Comparison - Feature-by-feature comparison of two phonemes with similarity score 4. Search by Features - Find all phonemes matching specific feature combinations

Word Lookup

Search for any word (44,011 words available) to view comprehensive information across 9 property categories.

Phonological Complexity (4 properties)

Property Source Description Coverage
IPA CMU Dictionary International Phonetic Alphabet transcription 100%
Syllables Syllabification algorithm Number of syllables (1-5) 100%
Phonemes CMU Dictionary Number of phoneme segments (1-10+) 100%
WCM Stoel-Gammon (2010) Word Complexity Measure (0-15) ~95%
MSH Motor Speech Hierarchy Mean Syllable Height (1-6) ~95%

Word Complexity Measure (WCM): 8-parameter measure of phonological complexity: 1. More than 2 syllables: +1 2. Non-initial stress: +1 3. Word-final consonant: +1 4. Consonant cluster: +1 per cluster 5. Velar (k, g, ŋ): +1 per occurrence 6. Liquid/rhotic (l, ɹ): +1 per occurrence 7. Fricative/affricate (f, v, θ, ð, s, z, ʃ, ʒ, h, tʃ, dʒ): +1 per occurrence 8. Voiced fricative/affricate: +1 additional

Mean Syllable Height (MSH): Motor complexity based on developmental stages: - Stage I-II (1-2): Vowels, /h/ - Stage III (3): Bilabials (p, b, m), nasals (n, ŋ) - Stage IV (4): Stops/glides (t, d, k, g, w, j) - Stage V (5): Fricatives (f, v, s, z, θ, ð, ʃ, ʒ) - Stage VI (6): Liquids/affricates (l, ɹ, ʧ, ʤ)

Psycholinguistic Properties (8 properties)

Lexical (2 properties):

Property Source Range Description Coverage
Frequency SUBTLEX-US (Brysbaert & New, 2009) 0-1000+ Occurrences per million words ~99%
Age of Acquisition Glasgow Norms (Scott et al., 2019) 1-7 Age when typically learned (1=earliest) ~75%

Semantic (3 properties):

Property Source Range Description Coverage
Imageability Glasgow Norms 1-7 Ease of mental imagery ~40%
Familiarity Glasgow Norms 1-7 Word familiarity ~40%
Concreteness Brysbaert et al. (2014) 1-5 Concrete vs. abstract ~60%

Affective (3 properties):

Property Source Range Description Coverage
Valence Warriner et al. (2013) 1-9 Negative to positive emotion ~50%
Arousal Warriner et al. (2013) 1-9 Calm to excited/intense ~50%
Dominance Warriner et al. (2013) 1-9 Weak to powerful/in-control ~50%

See Psycholinguistic Norms Reference for complete documentation of all 8 properties.

Example: Word Lookup for "strength"

Word: strength
IPA: /strɛŋkθ/

Phonological Complexity:
  Syllables: 1
  Phonemes: 7
  WCM: 11 (very high - 3-consonant cluster, velars, fricatives)
  MSH: 5.5 (high motor complexity - fricatives and velar nasal)

Lexical:
  Frequency: 28.5 (fairly common)
  Age of Acquisition: 5.8 (learned later)

Semantic:
  Imageability: 3.2 (abstract concept)
  Familiarity: 6.1 (familiar word)
  Concreteness: 2.5 (abstract)

Affective:
  Valence: 6.8 (positive)
  Arousal: 5.2 (moderately arousing)
  Dominance: 7.1 (high dominance/power)

Interpretation: "Strength" has very high phonological complexity (WCM=11) due to the initial 3-consonant cluster /str/ and multiple late-developing phonemes. Despite this complexity, it's a familiar word learned in middle childhood (AoA=5.8). The semantic profile shows it's an abstract concept (low imageability and concreteness) with positive emotional valence and strong associations with power (high dominance).

Phoneme Lookup

View detailed features for any IPA phoneme using the articulatory feature system (Hayes 2009; Moisik & Esling 2011).

Feature System Overview

38 ternary features across 7 categories: - Major class features (4): consonantal, syllabic, sonorant, approximant - Laryngeal features (11): voice, spreadGlottis, constrictedGlottis, etc. - Manner features (6): continuant, nasal, strident, lateral, delayedRelease, tap - Place features (articulator) (3): labial, coronal, dorsal - Place features (tongue body) (8): high, low, front, back, tense, etc. - Place features (detailed) (5): anterior, distributed, etc. - Vowel-specific (1): retractedTongueRoot

Feature values: - + : Feature is present - - : Feature is absent - 0 : Feature is not applicable (e.g., "nasal" for vowels)

Coverage: 39 English phonemes (General American English)

Complete Data & Methods Reference

Major Class Features (4 features)

Feature + - 0 Definition
consonantal Obstruents, nasals, liquids (p, t, k, s, n, l, ɹ) Vowels, glides (i, u, w, j) - Constriction in oral cavity
syllabic Vowels (i, æ, u) Consonants (p, t, k, s) - Can form syllable nucleus
sonorant Vowels, nasals, liquids, glides (i, n, l, w) Obstruents (p, t, k, s, f) - Spontaneous voicing possible
approximant Glides, liquids (w, j, l, ɹ) Obstruents, vowels - Close approximation without turbulence

Key distinction: Obstruents have sonorant:-, sonorants have sonorant:+. This is the major class difference used in maximal opposition.

Laryngeal Features (11 features)

Feature + - 0 Definition
voice Voiced sounds (b, d, g, z, v, m, n, all vowels) Voiceless sounds (p, t, k, s, f, θ) - Vocal fold vibration during articulation
spreadGlottis Aspirated sounds (pʰ, tʰ, kʰ, h) Non-aspirated - Glottis spread for aspiration
constrictedGlottis Glottalized sounds (ʔ) Non-glottalized - Glottis constricted
stiffVocalFolds Voiceless obstruents (p, t, k, s, f) Voiced obstruents, sonorants Vowels, sonorants Vocal folds stiffened
slackVocalFolds Breathy voiced (rare in English) Most sounds - Vocal folds slackened
periodicGlottalSource Voiced sounds (all vowels, b, d, g, m, n) Voiceless sounds (p, t, k, s, f) - Periodic vibration of vocal folds
epilaryngealSource Pharyngealized sounds Most English sounds - Epilaryngeal constriction
raisedLarynxEjective Ejectives (not in English) Most sounds - Raised larynx for ejection
loweredLarynxImplosive Implosives (not in English) Most sounds - Lowered larynx for implosion
constricted Tense vowels (i, u) Lax vowels (ɪ, ʊ) Consonants Pharyngeal constriction
fortis Voiceless obstruents (p, t, k, s) Voiced obstruents (b, d, g, z) Sonorants Greater articulatory force

Note: Many laryngeal features correlate with voicing. Voiceless obstruents typically have stiffVocalFolds:+ and fortis:+, while voiced obstruents have these features as -.

Manner Features (6 features)

Feature + - 0 Definition
continuant Fricatives, approximants (f, s, w, ɹ, vowels) Stops, affricates, nasals (p, t, k, tʃ, m) - Airflow continues through oral cavity
nasal Nasal consonants (m, n, ŋ) Oral sounds (all others) - Airflow through nasal cavity
strident Sibilants, labiodentals (s, z, ʃ, ʒ, f, v, tʃ, dʒ) Non-sibilants (θ, ð, p, t) Sonorants, vowels High-amplitude frication noise
lateral Lateral approximants (l) Central sounds (all others) - Airflow along sides of tongue
delayedRelease Affricates (tʃ, dʒ) Stops, fricatives (p, t, s) - Gradual release from closure
tap Flaps/taps (rare in standard American English) All others - Ballistic tongue movement

Key for intervention: continuant distinguishes stops/affricates (-) from fricatives (+). strident identifies high-noise fricatives.

Place Features - Articulator (3 features)

Feature + - Definition
labial Bilabials, labiodentals (p, b, m, f, v, w) Non-labials (t, d, k, s) Lips involved in articulation
coronal Alveolars, dentals, palatals (t, d, s, z, θ, ð, ʃ, ʒ, n, l, ɹ) Non-coronals (p, k, m) Tongue blade/tip raised
dorsal Velars, back vowels (k, g, ŋ, u, ʊ, o, ɔ, ɑ) Non-dorsals (p, t, s, i, e) Tongue body raised toward velum

Note: Multiple place features can be active simultaneously: - /w/: labial:+, dorsal:+ (both lips and tongue back) - /j/: coronal:+, dorsal:+ (both tongue blade and body)

Place Features - Tongue Body (8 features)

Feature + - 0 Definition
high High vowels, palatals (i, ɪ, u, ʊ, j) Mid/low vowels (e, ɛ, æ, ɑ) Most consonants Tongue body raised
low Low vowels (æ, ɑ, ɔ) Mid/high vowels (i, e, u) Most consonants Tongue body lowered
front Front vowels, palatals (i, ɪ, e, ɛ, æ, j) Back vowels (u, ʊ, o, ɔ, ɑ) Most consonants Tongue body fronted
back Back vowels, velars (u, ʊ, o, ɔ, ɑ, k, g, ŋ, w) Front vowels (i, e, æ) Most consonants Tongue body backed
tense Tense vowels (i, e, u, o) Lax vowels (ɪ, ɛ, ʊ, ɔ) Consonants Greater muscular tension
retractedTongueRoot RTR vowels (rare in English) Most English vowels - Tongue root retracted
advancedTongueRoot ATR vowels (tense vowels in some analyses) Lax vowels - Tongue root advanced
raisedLarynx Some tense vowels Most sounds - Larynx raised during articulation

Vowel space: The features high, low, front, back, and tense define the vowel space: - /i/: high:+, front:+, tense:+ (high front tense) - /ɪ/: high:+, front:+, tense:- (high front lax) - /æ/: low:+, front:+, tense:- (low front lax) - /ɑ/: low:+, back:+, tense:- (low back lax)

Place Features - Detailed (5 features)

Feature + - 0 Definition
anterior Labials, dentals, alveolars (p, t, s, θ, m, n, l) Palatals, velars (ʃ, k, g, ŋ, j) Vowels Articulated at or in front of alveolar ridge
distributed Palatals, dentals, laterals (ʃ, θ, l) Alveolars (t, s) Vowels Longer constriction along midline
strident (see Manner features)
labialDental Labiodentals (f, v) All others - Lower lip against upper teeth
retroflexed Rhotic sounds (/ɹ/ in some dialects) Most sounds - Tongue tip curled back

Note: anterior distinguishes sounds articulated further forward (+) from those further back (-).

Example: Phoneme Lookup for /k/

Phoneme: /k/
Type: Consonant (stop)

Major Class:
  consonantal: +
  syllabic: -
  sonorant: -
  approximant: -

Laryngeal:
  voice: -
  spreadGlottis: + (in word-initial position)
  periodicGlottalSource: -
  stiffVocalFolds: +
  fortis: +

Manner:
  continuant: -
  nasal: -
  strident: 0
  lateral: -
  delayedRelease: -

Place (Articulator):
  labial: -
  coronal: -
  dorsal: +

Place (Tongue Body):
  high: +
  low: -
  front: -
  back: +

Place (Detailed):
  anterior: -

Interpretation: /k/ is a voiceless velar stop. It's an obstruent (sonorant:-), not continuous (continuant:-), and articulated with the tongue body raised toward the velum (dorsal:+, high:+, back:+). In word-initial position, it's typically aspirated (spreadGlottis:+).

Phoneme Comparison

Compare two phonemes feature-by-feature to understand minimal pairs, maximal opposition, and phonological relationships.

Comparison Algorithm

  1. Feature-by-feature comparison: Compare all 38 articulatory features
  2. Count agreements: Features where both phonemes have the same value (+, -, or 0)
  3. Count differences: Features where phonemes have different values
  4. Compute similarity: similarity = agreements / (agreements + differences)
  5. Identify major class difference: Check if sonorant features differ

Similarity Score Interpretation

Score Range Interpretation Typical Relationships
0.95-1.0 Minimal pair Voicing pairs (t/d, k/g), single feature difference
0.85-0.94 Very similar Same place/manner, minor differences
0.70-0.84 Similar Same major class, different place or manner
0.60-0.69 Moderate Different manner within same major class
< 0.60 Very different Different major class (obstruent vs. sonorant)

Major class difference: If sonorant values differ, phonemes belong to different major classes (obstruent vs. sonorant). This receives +100 bonus in maximal opposition scoring.

Example 1: /t/ vs /d/ (Minimal Pair - Voicing)

Phoneme 1: /t/ (voiceless alveolar stop)
Phoneme 2: /d/ (voiced alveolar stop)

Shared Features (36 matching):
  consonantal: +
  syllabic: -
  sonorant: -
  approximant: -
  continuant: -
  nasal: -
  labial: -
  coronal: +
  dorsal: -
  anterior: +
  ... (and 26 more)

Different Features (2):
  voice: /t/ = - | /d/ = +
  periodicGlottalSource: /t/ = - | /d/ = +

Similarity Score: 36 / (36 + 2) = 0.947

Major Class Difference: NO (both sonorant:-)

Interpretation: /t/ and /d/ are a canonical minimal pair differing only in voicing. They share 36 of 38 features, resulting in very high similarity (0.947). Because they're both obstruents (sonorant:-), there's no major class difference.

Example 2: /s/ vs /l/ (Maximal Opposition)

Phoneme 1: /s/ (voiceless alveolar fricative)
Phoneme 2: /l/ (voiced alveolar lateral approximant)

Shared Features (24 matching):
  consonantal: +
  syllabic: -
  labial: -
  coronal: +
  dorsal: -
  anterior: +
  ... (and 18 more)

Different Features (14):
  sonorant: /s/ = - | /l/ = + ⭐ MAJOR CLASS DIFFERENCE
  approximant: /s/ = - | /l/ = +
  voice: /s/ = - | /l/ = +
  continuant: /s/ = + | /l/ = +
  strident: /s/ = + | /l/ = -
  lateral: /s/ = - | /l/ = +
  periodicGlottalSource: /s/ = - | /l/ = +
  stiffVocalFolds: /s/ = + | /l/ = -
  fortis: /s/ = + | /l/ = -
  ... (and 5 more)

Similarity Score: 24 / (24 + 14) = 0.632

Major Class Difference: YES (sonorant: - vs +)

Maximal Opposition Score: 14 + 100 = 114

Interpretation: /s/ and /l/ differ in 14 features AND belong to different major classes (obstruent vs. sonorant). This qualifies as maximal opposition - many feature differences plus a major class distinction. Research suggests this promotes broader phonological system reorganization.

Example 3: /i/ vs /ɪ/ (Tense/Lax Vowel Pair)

Phoneme 1: /i/ (high front tense vowel)
Phoneme 2: /ɪ/ (high front lax vowel)

Shared Features (35 matching):
  consonantal: -
  syllabic: +
  sonorant: +
  voice: +
  high: +
  front: +
  low: -
  back: -
  ... (and 27 more)

Different Features (3):
  tense: /i/ = + | /ɪ/ = -
  advancedTongueRoot: /i/ = + | /ɪ/ = -
  constricted: /i/ = + | /ɪ/ = -

Similarity Score: 35 / (35 + 3) = 0.921

Major Class Difference: NO (both sonorant:+)

Interpretation: /i/ and /ɪ/ differ primarily in tenseness, with /i/ being more tense and having advanced tongue root. They share most features, resulting in high similarity (0.921).

Search by Features

Find all phonemes matching specific feature combinations. Useful for identifying sound classes, planning intervention hierarchies, or understanding phonological patterns.

Search Algorithm

  1. Select features: Choose from 38 articulatory features
  2. Set values: Specify +, -, or 0 for each selected feature
  3. Filter phonemes: Return all phonemes where ALL specified features match (AND logic)
  4. Display results: Show matching phonemes with full feature matrices

Logic: All specified features must match (conjunction). Unspecified features are ignored.

Common Sound Class Searches

Obstruents

Find all obstruents: 

consonantal: +
sonorant: -

Results (16): p, b, t, d, k, g, f, v, θ, ð, s, z, ʃ, ʒ, tʃ, dʒ

Sonorants

Find all sonorants (non-vowels): 

consonantal: +
sonorant: +

Results (6): m, n, ŋ, l, ɹ, (and possibly w, j depending on analysis)

Fricatives

Find all fricatives: 

consonantal: +
sonorant: -
continuant: +

Results (10): f, v, θ, ð, s, z, ʃ, ʒ, h, (and possibly more)

Stops

Find all stops: 

consonantal: +
sonorant: -
continuant: -
delayedRelease: -

Results (6): p, b, t, d, k, g

Voiced Stops

Find all voiced stops: 

consonantal: +
sonorant: -
continuant: -
delayedRelease: -
voice: +

Results (3): b, d, g

Voiceless Stops

Find all voiceless stops: 

consonantal: +
sonorant: -
continuant: -
delayedRelease: -
voice: -

Results (3): p, t, k

Nasals

Find all nasals: 

consonantal: +
sonorant: +
nasal: +

Results (3): m, n, ŋ

Liquids

Find all liquids: 

consonantal: +
sonorant: +
approximant: +
nasal: -

Results (2): l, ɹ

Front Vowels

Find all front vowels: 

consonantal: -
syllabic: +
front: +

Results (5): i, ɪ, e, ɛ, æ

High Vowels

Find all high vowels: 

consonantal: -
syllabic: +
high: +

Results (4): i, ɪ, u, ʊ

Tense Vowels

Find all tense vowels: 

consonantal: -
syllabic: +
tense: +

Results (5): i, e, u, o, ɔ (varies by dialect)

Sibilants

Find all sibilants: 

consonantal: +
strident: +
continuant: +

Results (6): s, z, ʃ, ʒ, (plus affricates tʃ, dʒ with delayedRelease:+)

Advanced Searches

Alveolar Obstruents

Find all alveolar obstruents: 

consonantal: +
sonorant: -
coronal: +
anterior: +

Results (6): t, d, s, z (and potentially θ, ð depending on features)

Back Rounded Vowels

Find all back rounded vowels: 

consonantal: -
syllabic: +
back: +

Results (4): u, ʊ, o, ɔ (Note: rounding not directly encoded, inferred from backness in English)

Late-Developing Sounds (Approximation)

Find fricatives and affricates (late-developing classes): 

consonantal: +
sonorant: -
continuant: +

Results: All fricatives

OR

delayedRelease: +

Results: All affricates (tʃ, dʒ)

Performance Characteristics

Operation Time Notes
Word lookup < 5 ms O(1) hash table lookup
Phoneme lookup < 1 ms O(1) direct access to feature matrix
Phoneme comparison < 1 ms O(38) feature-by-feature comparison
Search by features < 10 ms O(39 × F) where F = number of features
Full feature matrix display < 5 ms Rendering 38 features

Factors Affecting Speed: - Number of features specified (more features = slightly faster filtering) - Browser rendering (MUI table rendering is the bottleneck) - Result set size (larger results = slower display)

Data: All lookups query the Hono/D1 backend on Cloudflare Workers.

Vocabulary and Coverage

Category Coverage Notes
Words 44,011 CMU Pronouncing Dictionary (primary pronunciations)
Phonemes 39 General American English
Phonological properties 100% Syllables, phonemes, IPA
WCM/MSH ~95% Computed for most words
Psycholinguistic norms 40-99% Varies by property (see tables above)
Dialect General American Primary pronunciations only

Excluded: - Pronunciation variants (CMU entries with (1), (2), etc.) - Proper nouns - Non-English loanwords without standard pronunciations

Tips and Best Practices

Word Lookup

  • Case-insensitive: "cat", "Cat", "CAT" all work
  • Exact match required: Searches for "cat" won't find "cats"
  • Missing data: Properties without values display as "—" or "N/A"
  • IPA display: Uses Unicode IPA characters

Phoneme Lookup

  • Exact IPA required: Use the IPA keyboard or copy-paste
  • Case-sensitive: /i/ ≠ /ɪ/ (different phonemes)
  • Coverage: 39 English phonemes (vowels, consonants, glides)

Phoneme Comparison

  • Use for minimal pairs: Compare sounds that differ in one feature (e.g., /t/ vs /d/)
  • Use for maximal opposition: Compare sounds with major class difference (e.g., /s/ vs /l/)
  • Similarity score: 0.0-1.0, higher = more similar
  • Major class difference: Look for sonorant value difference

Search by Features

  • Start broad: Begin with major class features (consonantal, sonorant)
  • Refine incrementally: Add features one at a time
  • Use AND logic: All specified features must match
  • Check coverage: Some features are not applicable to all phonemes

Use Cases

Clinical Practice

  1. Understanding error patterns: Compare target phoneme to substitution (e.g., /k/ vs /t/ for fronting)
  2. Planning intervention: Find maximal opposition pairs (major class difference + many features)
  3. Identifying sound classes: Search for fricatives, stops, nasals for treatment hierarchies
  4. Word selection: Look up words to ensure appropriate complexity (WCM, MSH) and frequency

Research

  1. Stimulus control: Match words on frequency, AoA, imageability, concreteness
  2. Phonological variables: Select words by phoneme count, syllable count, complexity
  3. Semantic variables: Control for concreteness, imageability, familiarity
  4. Affective content: Select words by valence, arousal, dominance
  5. Feature analysis: Compare phoneme inventories across sound classes

Education

  1. Phonology instruction: Explore distinctive features and sound classes
  2. Minimal pairs: Find pairs differing in single features
  3. Vowel space: Examine front/back, high/low, tense/lax distinctions
  4. Consonant inventory: Understand place, manner, voicing contrasts

References

Articulatory Features: - Hayes, B. (2009). Introductory Phonology. Wiley-Blackwell. - Moisik, S. R., & Esling, J. H. (2011). The 'whole larynx' approach to laryngeal features. ICPhS XVII, 1406-1409.

Phonological Complexity: - Stoel-Gammon, C. (2010). The Word Complexity Measure: Description and application to developmental phonology and disorders. Clinical Linguistics & Phonetics, 24(4-5), 271-282. - Namasivayam, A. K., et al. (2021). Milestones of speech production in children. Journal of Speech, Language, and Hearing Research.

Psycholinguistic Norms: - Brysbaert, M., & New, B. (2009). Moving beyond Kučera and Francis. Behavior Research Methods, 41(4), 977-990. - Brysbaert, M., et al. (2014). Concreteness ratings for 40 thousand English words. Behavior Research Methods, 46, 904-911. - Scott, G. G., et al. (2019). The Glasgow Norms: Ratings of 5,500 words. Behavior Research Methods, 51, 1258-1270. - Warriner, A. B., et al. (2013). Norms of valence, arousal, and dominance. Behavior Research Methods, 45, 1191-1207.

See Also