Overview
Introduction
Stretching out vowels for a 'drawn-out' or exclamatory speech effect, like turning 'hi' into 'hii', is a common informal writing trick that's fiddly to apply consistently by hand across a whole passage.
It runs entirely client-side, so nothing you paste is ever uploaded to a server.
What Is Vowel Duplicator?
A vowel duplicator that inserts a copy of each vowel, a, e, i, o, and u in either case, immediately after itself.
It runs entirely client-side as part of this site's String Tools collection, so nothing you paste is ever uploaded to a server.
How Vowel Duplicator Works
The tool scans the input with a regular expression matching any vowel and replaces each match with two copies of itself, preserving the original case.
The transformation happens synchronously in JavaScript the moment you type, with no network round trip involved.
When To Use Vowel Duplicator
Use it to create a stretched, exclamatory, or stylized speech effect in dialogue or captions, or to stress-test a UI with doubled vowel characters.
It's a fast way to get the answer without opening a code editor, a REPL, or writing a one-off script just to check.
Often used alongside Vowel Replacer and Vowel Remover.
Features
Advantages
- Preserves the case of every duplicated vowel automatically.
- Leaves consonants and punctuation completely untouched.
- Replaces via a callback on the matched character, so each doubled vowel always carries the same case as the original.
Limitations
- Doesn't treat 'y' as a vowel, matching the standard five-vowel definition.
- Matches only the five ASCII vowels, so accented forms such as 'é' or 'ü' pass through undoubled.
Examples
Best Practices & Notes
Best Practices
- Use it sparingly on short words or phrases for the clearest stylistic effect.
- Keep the input short, since the effect reads as drawn-out speech across a word or two but as noise across a paragraph.
- Check the result where it will be used, because doubled vowels defeat spell-checking and are read out literally by screen readers.
Developer Notes
The transform is `input.replace(/[aeiouAEIOU]/g, (vowel) => vowel + vowel)`, so the replacement function's argument is always the exact matched character, keeping the duplication case-accurate without extra logic.
Vowel Duplicator Use Cases
- Creating stretched, exclamatory dialogue or captions
- Building stylized display text for a creative project
- Stress-testing a font or layout with doubled vowel characters
Common Mistakes
- Expecting 'y' to be duplicated as a vowel; it's intentionally excluded.
- Applying it to long passages, which can make the doubled text hard to read.
Tips
- Pair with the Consonant Duplicator if you want every letter in the text doubled instead of just vowels.
- Only vowels grow, so the output length increases by exactly the vowel count, which is roughly 40% for ordinary English text.