Stan Runge
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Dutch and Korean (explained in English) and English (explained in Dutch) from A1 to C1, with a Hangul level for Korean. Lessons with notes, words and sentences generate multiple-choice, typing, sentence building, cloze, listening and matching exercises. Endless challenges: a seeded daily challenge, sprint, survival, mixed practice, level tests, spaced-repetition reviews and generated drills (numbers, clock times, de/het, plurals, Dutch and Korean conjugation, particles, Hangul reading, irregular verbs). Progress is stored in localStorage with export/import. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
44 lines
1.5 KiB
TypeScript
44 lines
1.5 KiB
TypeScript
/** Text-to-speech through the browser's built-in voices; no audio files or services. */
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const supported = () => typeof window !== 'undefined' && 'speechSynthesis' in window;
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function voices(): Promise<SpeechSynthesisVoice[]> {
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if (!supported()) return Promise.resolve([]);
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const now = speechSynthesis.getVoices();
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if (now.length) return Promise.resolve(now);
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return new Promise((resolve) => {
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const done = () => resolve(speechSynthesis.getVoices());
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speechSynthesis.addEventListener('voiceschanged', done, { once: true });
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setTimeout(done, 1500);
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});
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}
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const matches = (voice: SpeechSynthesisVoice, lang: string) =>
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voice.lang.replace('_', '-').toLowerCase().startsWith(lang.slice(0, 2).toLowerCase());
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function best(list: SpeechSynthesisVoice[], lang: string) {
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const candidates = list.filter((v) => matches(v, lang));
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return (
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candidates.find(
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(v) => v.lang.replace('_', '-').toLowerCase() === lang.toLowerCase() && !v.localService
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) ??
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candidates.find((v) => v.lang.replace('_', '-').toLowerCase() === lang.toLowerCase()) ??
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candidates[0]
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);
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}
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export async function hasVoice(lang: string): Promise<boolean> {
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return !!best(await voices(), lang);
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}
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export async function speak(text: string, lang: string, rate = 0.9) {
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if (!supported()) return;
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const voice = best(await voices(), lang);
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speechSynthesis.cancel();
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const utterance = new SpeechSynthesisUtterance(text);
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utterance.lang = lang;
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utterance.rate = rate;
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if (voice) utterance.voice = voice;
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speechSynthesis.speak(utterance);
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}
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