Kumo

Kumo is a male 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 purpose

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: “今朝はコーヒーをいれる前に窓を開けました。通りはまだ静かで、木の下を自転車がゆっくり通っていきます。今日やることを三つだけ書き出してから、まずは朝ごはんをゆっくり食べることにしました。急がない時間があるだけで、いつもの朝が少しやわらかく感じられます。” 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 is a warning band: the asset is intelligible but the render may sound strained, so keep phrases short and check every one you export.

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 98340afd, 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: Alpha (female, grade C+), Gongitsune (female, grade C), Nezumi (female, grade C-). Switching between them on the same sentence is the fastest way to hear whether one suits the script better.

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