Last updated: July 8, 2026
Kotoba is a free, voice-first Japanese vocabulary trainer at kotobaapp.com. By using it you agree to these terms and to the Privacy Policy. If you don't agree, please don't use the service.
You can use Kotoba without an account; an account (sign-in by emailed code) adds progress sync across devices. You're responsible for keeping access to your email address secure, since anyone with it can sign in as you. You must be at least 13 to create an account.
Use Kotoba for personal language study. Don't abuse the service — no attempting to disrupt it, probe or overload its infrastructure, scrape it at volume, or use it to harass anyone (including through the feedback form). We may suspend accounts that do.
Kotoba was built with the assistance of artificial intelligence: example sentences, translations, and audio are largely AI-generated (with human review), parts of the app's code were written with AI tools, and some exercises are graded by an AI model. We work to keep the content accurate, but AI-generated material can contain errors — treat Kotoba as a study aid, not an authoritative reference. If you spot a mistake, please report it with the in-app form.
Answering by voice requires microphone access, which your browser will ask for and which you can decline — every exercise also works with the on-screen buttons. See the Privacy Policy for how voice audio is processed.
JLPT word lists are by Jonathan Waller, used under CC-BY. The app's source code is available on GitHub under its repository license. If you send feedback or suggestions, you grant us the right to use them to improve the service without obligation to you.
Kotoba is provided free of charge, "as is" and "as available", without warranties of any kind, express or implied — including fitness for a particular purpose, accuracy of content, or uninterrupted availability. The service may change or be discontinued at any time.
To the maximum extent permitted by law, Kotoba and its creator are not liable for any indirect, incidental, or consequential damages arising from your use of the service. Our total liability for any claim is limited to the amount you paid us to use Kotoba — which is zero.
You can stop using Kotoba at any time and request deletion of your data (see the Privacy Policy). We may suspend or terminate access for abuse of these terms.
These terms are governed by the laws of the State of California, without regard to its conflict-of-law rules. Any dispute arising from these terms or the service will be resolved in the state or federal courts located in Los Angeles County, California, and you consent to their jurisdiction.
We may update these terms; material changes will be reflected in the date above and noted on the site. Continued use after a change means you accept the new terms.
Questions about these terms? Use the in-app feedback form or open an issue on GitHub.