I created it as a small project to learn about modern WebExtensions, and because I was curious about the psychological impact of reading English written just as it is pronounced. It uses the great CMU pronunciation dictionary, which gives you General American pronunciation.
Please report any bugs on GitHub, and feel free to send me feedback through this site’s comment section or via email.
Why use IPA?
Japanese famously uses Kanji, a logographic system initially developed as a way to write Chinese, for most of its writing. Of course, Chinese is an analytic, or non-inflected, language, whereas Japanese is heavily inflected. That’s problematic because logographic systems don’t work great with inflected languages, so Japanese has to tack on other families of symbols to write down its speech.
But Japanese isn’t the only language with an ill-adapted writing system. English is written using the Latin alphabet, which has 5 (and a half) vowel symbols. That’s great if you have 5 (and a half) vowels like Spanish, but if you have 15 like General American English, it makes spelling tricky… The IPA, on the other hand, is able to represent all of these 15 sounds.
Another reason I personally find this interesting is that I tend to strongly associate words with their spelling; I’m sometimes surprised to realize that two words which are spelled very differently are pronounced almost the same. Reading an IPA transcription will help you see some of these similarities.