Alpha

Alpha is a female Japanese AI voice rated C+ on the OfflineTTS quality scale. Speech synthesis runs in your browser with no signup or per-character fees.

Best for: General voice-over

Quality rating explained: C+ is a catalog discovery label, not a measured MOS score, a public leaderboard position, or a guarantee for your script. Audition names, numbers, pacing, and chunk joins before publishing.

Non-English Kokoro voices use the lightweight OfflineTTS phonemization service for pronunciation tokens, followed by local WebGPU/WASM waveform generation on your device.

Preview transcript: the sample player above reads: “帰り道に小さな商店へ寄って、みかんと食パンを買いました。レジの人に、今夜は誰か来るのですかと聞かれて、いいえと答えました。でもその一言で、ただの火曜日の夕食が少し楽しみになりました。家に着いたらスープを温めて、好きな音楽を一曲流すつもりです。” Listen to that clip before generating your own text; it is the shortest way to judge pronunciation, pace, and whether the Japanese phonemization path fits your script.

Reviewing Japanese text with this preset: Japanese timing is mora-based rather than syllable-based, and written text has no spaces between words. Numbers, counters, katakana loanwords, and kanji with several readings are where a synthesis draft usually needs a check, especially in names and addresses.

Grade context: A C+ grade marks a preset with audible artifacts on some material. It can work for short lines or character parts where texture matters more than polish.

What the browser downloads: For this Japanese preset, Kokoro needs phoneme tokens that the browser phonemizer does not produce, so the text is sent to the OfflineTTS phonemization endpoint before the local model synthesizes audio. The audio itself is still generated on your device.

Asset identity: this preset maps to the cached asset fingerprint 1bf4c9dc, so it can be told apart from a same-named voice on another engine even when the label in the picker looks identical.

Other Japanese voices: Gongitsune (female, grade C), Nezumi (female, grade C-), Tebukuro (female, grade C). Switching between them on the same sentence is the fastest way to hear whether one suits the script better.

Same name, different engine: “Alpha” also exists as a Hindi preset on Kokoro with a C catalog grade. Compare both on the same sentence before choosing, because the two assets were recorded, cloned, or trained separately and do not sound identical.

Explore other Japanese voices or browse the complete voice library for your project.