The divergence
Lexical diversity soars. Acoustic diversity stalls.
Shannon entropy measures how spread out a distribution is. Higher entropy means more even spread across more options. Below, one line tracks how many distinct spellings parents use; the other tracks how many distinct sounds those spellings produce. The widening gap between them is the acoustic monoculture.
Your acoustic neighbourhood
Type a name. See who sounds the same.
Every name maps to a phonetic code via Double Metaphone, an algorithm that strips a word down to its consonant skeleton — the way it actually moves through the mouth. Names that share a code are acoustically interchangeable to a casual listener, no matter how different they look on paper.
The dominant sounds
Fifteen phonetic codes that captured the most births
Each row is a single sound — a Double Metaphone code — with the most common spellings that map to it. The sparkline shows each sound's share of all births from 1880 to 2024. Some sounds are ancient and declining; others are modern invasions.
The raw numbers
Spellings vs sounds, decade by decade
The left axis shows the raw count of distinct spellings used in each year; the right axis shows distinct phonetic codes. The ratio between them — how many spellings map to each sound — is the multiplier shown on hover.
Cross-border anthropology
Three countries. One acoustic basin.
In 1920, the birth registries of the United States (SSA), England & Wales (ONS), and France (INSEE) were separate linguistic worlds dominated by heavy stop consonants. Today, all three have converged on the exact same acoustic corridors. Liam, Noah, Leo, Lucas, Olivia, Emma, Amelia, and Mia sit simultaneously in the top ranks of American, British, and French birth registries.
The Four Transnational Acoustic Corridors
Click any corridor to see how the United States, United Kingdom, and France populate the exact same phonetic territory.
Method and limits
What this measures and what it misses
Data sources
United States: Social Security Administration birth records, 1880–2024 (≥5 occurrences privacy threshold). United Kingdom: Office for National Statistics (ONS) birth registrations for England & Wales, 1904–2025. France: Institut National de la Statistique et des Études Économiques (INSEE) Fichier des prénoms, 1900–2025.
Phonetic algorithm
Double Metaphone reduces each name to a consonant-skeleton code (e.g. Jackson, Jaxon, Jaxsen → JKSN). It was designed for English-language names and handles many European borrowings well. It is not a full phonological analysis — it ignores vowel quality, stress, and tone. Two names sharing a code sound similar but not necessarily identical.
What entropy measures
Shannon entropy (in bits) measures how evenly births distribute across categories. If every baby received the same name, entropy would be 0. If births spread perfectly evenly across N names, entropy would be log₂(N). The lexical line tracks spellings; the phonetic line tracks sounds. The gap between them quantifies how much of the apparent diversity is cosmetic.
What this doesn't claim
Phonetic convergence is not the same as cultural conformity. Parents may have strong personal reasons for a spelling. The analysis shows that the acoustic output of naming choices is narrower than the visual output — an observation, not a judgment. The effect may differ in languages where orthography maps more consistently to pronunciation.