Great question—dealing with mispronounced proper nouns (like place names such as Glassell) in the Web Speech API is a super common pain point. The good news is you can solve this by leveraging Speech Synthesis Markup Language (SSML) to force exact phonetic pronunciations and adjust stress exactly how you need it. Let’s walk through the steps:

Use SSML <phoneme> Tags for Precise Pronunciation #

The Web Speech API supports SSML, which lets you wrap tricky words in <phoneme> tags to define their exact pronunciation using a phonetic alphabet. For English, the International Phonetic Alphabet (IPA) is the most reliable choice.

For your example: if Glassell is being mispronounced with stress on the first syllable ("GLA sl"), but you need stress on the second syllable (like "gluh-SELL"), here’s how you’d write the SSML:

<speak>
  Turn left on <phoneme alphabet="ipa" ph="ɡləˈsɛl">Glassell</phoneme> Street.
</speak>

• alphabet="ipa" tells the API we’re using IPA notation.
• The ˈ symbol in the ph attribute marks the stressed syllable—here, it’s placed before "sɛl" to shift the stress to the second part of the word.

Pass SSML to speechSynthesis #

To use SSML, you’ll create a SpeechSynthesisUtterance object, set the correct language (critical for phoneme parsing), and pass the SSML string as the text. Here’s a working JavaScript example:

const utterance = new SpeechSynthesisUtterance();
utterance.lang = 'en-US'; // Match the language of your phonemes
utterance.text = `
<speak>
  My favorite café is on <phoneme alphabet="ipa" ph="ɡləˈsɛl">Glassell</phoneme> Street.
</speak>
`;

if ('speechSynthesis' in window) {
  speechSynthesis.speak(utterance);
}

Tweak and Test Phonemes #

If the first try isn’t perfect, adjust the IPA string. You can look up the correct IPA for any word using a dictionary that provides IPA transcriptions, or use tools to listen to the desired pronunciation and transcribe it. A quick note: some voices may support X-SAMPA as an alternative to IPA, but IPA is more widely supported in modern browsers.

Streamline for Multiple Custom Pronunciations #

If you have lots of tricky words, store them in a dictionary object to automatically replace them in your text before passing it to the utterance. This saves you from manually wrapping every instance:

// Define your custom pronunciations
const customPronunciations = {
  'Glassell': '<phoneme alphabet="ipa" ph="ɡləˈsɛl">Glassell</phoneme>',
  'La Jolla': '<phoneme alphabet="ipa" ph="lə ˈhɔɪə">La Jolla</phoneme>',
  // Add more words here
};

// Function to replace words in text
function applyCustomPronunciations(text) {
  return text.replace(/\b(Glassell|La Jolla)\b/g, match => customPronunciations[match]);
}

// Usage
const originalText = "I’m meeting you at the corner of Glassell and La Jolla.";
const ssmlText = `<speak>${applyCustomPronunciations(originalText)}</speak>`;
utterance.text = ssmlText;

Quick Edge Case Check #

• Ensure the voice you’re using supports SSML: most built-in voices (Apple’s Siri voices, Google’s Text-to-Speech voices) do, but some third-party voices might not. You can test this by running your SSML with different voices from speechSynthesis.getVoices().

内容的提问来源于stack exchange，提问作者Coco