Terms of Service

Last updated: October 2, 2026

Article 1

Application

These Terms of Service set out the conditions for using the Korean vocabulary learning service (the "Service") provided by Hanglass (the "App"). By using the Service, you (the "User") agree to these Terms.

Any rules, guidelines, or notices displayed within the Service form part of these Terms regardless of their name. In the event of a conflict, these Terms take precedence.

Article 2

Definitions

The following terms are defined as follows in these Terms.

  1. "Operator": the person or entity that provides and operates the Service
  2. "Learning Data": information generated or stored through use of the Service, including study history, review schedules, achievements, and settings
  3. "Third-Party Service": a service provided by a third party used to deliver the Service (e.g., authentication, data storage, advertising, analytics)
  4. "Content": all information displayed or provided within the Service, including vocabulary, descriptions, images, audio, and UI elements
  5. "Plus Plan": a plan that allows use of the paid features of the Service
  6. "High-Quality Speech": AI-synthesized speech generated on the device, available to a User who has a Plus Plan entitlement and has downloaded the speech model
  7. "Speech Model": Supertonic 3 and its derivatives, used to generate High-Quality Speech
Article 3

Service Content and Conditions

The Service is designed to support Korean vocabulary learning and review, and provides features such as browsing word sets, studying, reviewing, and viewing progress. The operator may change, add, suspend, or terminate all or part of the Service without prior notice to users.

Users are responsible for the devices, OS, network connections, and associated costs required to use the Service. The operator is not liable for issues arising from the user's environment.

Article 4

Account and Cloud Sync

Some features (such as cloud sync) may require account creation or login through the operator or a third-party service. Users are responsible for managing their account information and must not allow third parties to use their account.

The availability and scope of learning data sync, backup, and restoration may vary depending on user settings, subscription plan, network conditions, and third-party service specifications. The operator is not liable for failure to sync or for loss or corruption of learning data, except in cases of willful misconduct or gross negligence by the operator.

Article 5

Fees and Billing

The Service includes both free and paid features (Plus Plan). The content and pricing of paid features are as displayed within the Service.

  1. Plan Types The Service may offer monthly subscriptions and annual subscriptions (auto-renewing). If you previously purchased a lifetime plan, that entitlement remains valid.
  2. Auto-Renewal Subscriptions automatically renew 24 hours before the end of each period. The renewal charge is applied to the account within 24 hours before the renewal date.
  3. Cancellation Subscriptions must be cancelled through the Apple App Store or Google Play Store subscription settings. Cancellation cannot be processed within the Service itself.
  4. After Expiration Once a subscription expires, Plus features will no longer be accessible. Learning data will be retained, but access to Plus-only features and content will be suspended. The conditions for the high-quality speech feature are set out in Article 10.
  5. Restoring Purchases If a purchase was made with the same app store account, it may be possible to restore the purchase using the "Restore Purchases" feature within the Service.
  6. Refunds Refund eligibility and procedures are governed by the terms and policies of the respective app store (Apple App Store / Google Play Store). The operator is not responsible for refund decisions made by the app stores.
Article 6

Prohibited Activities

Users must not engage in any of the following activities when using the Service.

  1. Acts that violate laws or regulations, or that are contrary to public order and morals
  2. Acts related to criminal activity
  3. Acts that infringe on the intellectual property rights, privacy, reputation, or other rights and interests of the Service, the operator, third-party services, or other parties
  4. Unauthorized access, tampering, destruction, interference, or placing excessive load on systems, or attempts to do so
  5. Unauthorized use of Service content or data through reproduction, redistribution, sale, scraping, reverse engineering, decompilation, or similar means
  6. Acts that may interfere with the operation of the Service
  7. Providing benefits or other assistance to antisocial forces
  8. Any other acts deemed inappropriate by the operator
  9. Acts that violate the speech-model use restrictions set out in Article 10

If the operator determines that any of the above has occurred, it may take measures without prior notice, including restricting use, suspending accounts, or deleting data.

Article 7

Intellectual Property

All intellectual property rights in the Service's content, UI, design, programs, and other materials belong to the operator or the respective rights holders. Users must not use these beyond the scope of using the Service.

Learning data entered or stored by users within the Service belongs to the user. However, the operator may handle learning data to the extent necessary for providing, improving, preventing abuse of, and enhancing the quality of the Service.

Rights in the third-party speech model used for high-quality speech belong to the rights holder of that model. Users may use it only within the scope of Article 10 and the license in the Schedule.

Article 8

Advertising and Third-Party Services

The Service may display advertisements. The operator may not be able to control the content, frequency, or destinations of advertisements, and is not liable for damages arising therefrom, except in cases of willful misconduct or gross negligence.

The Service may integrate with third-party services. Use of those services is subject to their respective terms and policies. Any disputes between users and third-party service providers shall be resolved between the parties concerned.

Handling of personal information and other data within the Service is governed by the separately defined Privacy Policy.

Article 9

Disclaimer

The operator does not guarantee that the Service will produce specific learning outcomes (such as vocabulary retention or passing exams). The operator makes no warranty regarding the accuracy, completeness, usefulness, safety, or continuity of the Service's content.

The operator is not liable for damages to users caused by interruption, suspension, termination, unavailability, data loss, device failure, or communication failure of the Service, except in cases of willful misconduct or gross negligence by the operator.

High-quality speech is synthesized speech intended to assist learning. Its pronunciation and other accuracy are not guaranteed. Details are set out in Article 10.

Article 10

High-Quality Speech

The App's high-quality speech is AI-synthesized speech using Supertonic 3. It is not a human recording, and pronunciation, accent, and readings may be inaccurate. Speech is generated on the user's device.

Use of the high-quality speech feature requires a Plus Plan entitlement and a download of the speech model. The download requires communication charges and device storage. If the entitlement cannot be verified, or if there is a problem with the speech model or the device, the App may use standard speech. The speech model may remain on the device after the Plus Plan entitlement ends, but the high-quality speech feature cannot be used in that case.

Third-party model license and use restrictions

The Supertonic 3 model used for this feature, and derivatives of that model, are subject to the BigScience Open RAIL-M License dated August 18, 2022, set out in the Schedule. When using this feature, the User shall comply with the use-based restrictions in Section 5 and Attachment A of that license. Those restrictions form part of these Terms.

The User must not use the Model or Derivatives of the Model for the following purposes. The following explains the use restrictions and does not narrow the restrictions stated in the license text.

  1. Any use that violates any applicable national, federal, state, local, or international law or regulation.
  2. Exploiting, harming, or attempting to exploit or harm minors in any way.
  3. Generating or disseminating verifiably false information and/or content with the purpose of harming others.
  4. Generating or disseminating personal identifiable information that can be used to harm an individual.
  5. Generating or disseminating information and/or content (e.g. images, code, posts, articles), and placing the information and/or content in any context (e.g. a bot generating tweets), without expressly and intelligibly disclaiming that the information and/or content is machine generated.
  6. Defaming, disparaging, or otherwise harassing others.
  7. Impersonating or attempting to impersonate (e.g. deepfakes) others without their consent.
  8. Fully automated decision making that adversely impacts an individual's legal rights or otherwise creates or modifies a binding, enforceable obligation.
  9. Any use intended to, or which has the effect of, discriminating against or harming individuals or groups based on online or offline social behavior or known or predicted personal or personality characteristics.
  10. Exploiting any of the vulnerabilities of a specific group of persons based on their age, social, physical, or mental characteristics, in order to materially distort the behavior of a person pertaining to that group in a manner that causes or is likely to cause that person or another person physical or psychological harm.
  11. Any use intended to, or which has the effect of, discriminating against individuals or groups based on legally protected characteristics or categories.
  12. Providing medical advice and medical results interpretation.
  13. Generating or disseminating information for the purpose of being used for administration of justice, law enforcement, immigration, or asylum processes, such as predicting that an individual will commit fraud or a crime (e.g. by text profiling, drawing causal relationships between assertions made in documents, or indiscriminate and arbitrarily-targeted use).

A User who uses or shares generated speech shall also state that it is machine-generated and shall comply with the restrictions in the preceding paragraph. Responsibility for use of the output follows applicable law and these Terms. It is not guaranteed that generated speech does not infringe third-party rights.

Fees for the Plus Plan are charged for use of the App's features and services. They do not confer an exclusive right in the Supertonic 3 model. These Terms do not limit rights granted to the User under the third-party license.

Model attribution

The original model is Supertone / Supertonic 3. The distributed model obtained by the App is sherpa-onnx-supertonic-3-tts-int8-2026-05-11. Changes made by the distributor are INT8 quantization of the ONNX model and binarization of voice styles and the Unicode index. The App has not changed the model weights. Mention of these names does not indicate endorsement or warranty of the App by the rights holders.

Original model license: https://huggingface.co/Supertone/supertonic-3/blob/724fb5a/LICENSE

Conversion source: https://github.com/k2-fsa/sherpa-onnx/blob/f69171f/scripts/supertonic/run.sh

The full license text is set out in the following Schedule.

Schedule

BigScience Open RAIL-M License

This Schedule sets out the original text of the BigScience Open RAIL-M License dated August 18, 2022, as referenced in Article 10.

Show full license text
BigScience Open RAIL-M License
dated August 18, 2022

Section I: PREAMBLE

This Open RAIL-M License was created by BigScience, a collaborative open innovation project aimed at
the responsible development and use of large multilingual datasets and Large Language Models
(“LLMs”). While a similar license was originally designed for the BLOOM model, we decided to adapt it
and create this license in order to propose a general open and responsible license applicable to other
machine learning based AI models (e.g. multimodal generative models).
In short, this license strives for both the open and responsible downstream use of the accompanying
model. When it comes to the open character, we took inspiration from open source permissive licenses
regarding the grant of IP rights. Referring to the downstream responsible use, we added use-based
restrictions not permitting the use of the Model in very specific scenarios, in order for the licensor to be
able to enforce the license in case potential misuses of the Model may occur. Even though downstream
derivative versions of the model could be released under different licensing terms, the latter will always
have to include - at minimum - the same use-based restrictions as the ones in the original license (this
license).
The development and use of artificial intelligence (“AI”), does not come without concerns. The world has
witnessed how AI techniques may, in some instances, become risky for the public in general. These risks
come in many forms, from racial discrimination to the misuse of sensitive information.
BigScience believes in the intersection between open and responsible AI development; thus, this License
aims to strike a balance between both in order to enable responsible open-science in the field of AI.
This License governs the use of the model (and its derivatives) and is informed by the model card
associated with the model.

NOW THEREFORE, You and Licensor agree as follows:

1. Definitions
(a) "License" means the terms and conditions for use, reproduction, and Distribution as defined in
this document.
(b) “Data” means a collection of information and/or content extracted from the dataset used with the
Model, including to train, pretrain, or otherwise evaluate the Model. The Data is not licensed under
this License.
(c)“Output” means the results of operating a Model as embodied in informational content resulting
therefrom.
(d)“Model” means any accompanying machine-learning based assemblies (including checkpoints),
consisting of learnt weights, parameters (including optimizer states), corresponding to the model
architecture as embodied in the Complementary Material, that have been trained or tuned, in whole or
in part on the Data, using the Complementary Material.
(e) “Derivatives of the Model” means all modifications to the Model, works based on the Model, or any
other model which is created or initialized by transfer of patterns of the weights, parameters,
activations or output of the Model, to the other model, in order to cause the other model to perform
similarly to the Model, including - but not limited to - distillation methods entailing the use of
intermediate data representations or methods based on the generation of synthetic data by the Model
for training the other model.
(f)“Complementary Material” means the accompanying source code and scripts used to define,
run, load, benchmark or evaluate the Model, and used to prepare data for training or evaluation, if
any. This includes any accompanying documentation, tutorials, examples, etc, if any.
(g) “Distribution” means any transmission, reproduction, publication or other sharing of the Model or
Derivatives of the Model to a third party, including providing the Model as a hosted service made
available by electronic or other remote means - e.g. API-based or web access.
(h) “Licensor” means the copyright owner or entity authorized by the copyright owner that is
granting the License, including the persons or entities that may have rights in the Model and/or
distributing the Model.
(i) "You" (or "Your") means an individual or Legal Entity exercising permissions granted by this
License and/or making use of the Model for whichever purpose and in any field of use, including
usage of the Model in an end-use application - e.g. chatbot, translator, image generator.
(j) “Third Parties” means individuals or legal entities that are not under common control with
Licensor or You.
(k) "Contribution" means any work of authorship, including the original version of the Model and
any modifications or additions to that Model or Derivatives of the Model thereof, that is
intentionally submitted to Licensor for inclusion in the Model by the copyright owner or by an
individual or Legal Entity authorized to submit on behalf of the copyright owner. For the
purposes of this definition,
“submitted” means any form of electronic, verbal, or written
communication sent to the Licensor or its representatives, including but not limited to
communication on electronic mailing lists, source code control systems, and issue tracking
systems that are managed by, or on behalf of, the Licensor for the purpose of discussing and
improving the Model, but excluding communication that is conspicuously marked or otherwise
designated in writing by the copyright owner as "Not a Contribution."
(l) "Contributor" means Licensor and any individual or Legal Entity on behalf of whom a
Contribution has been received by Licensor and subsequently incorporated within the Model.


Section II: INTELLECTUAL PROPERTY RIGHTS

Both copyright and patent grants apply to the Model, Derivatives of the Model and Complementary
Material. The Model and Derivatives of the Model are subject to additional terms as described in Section III.

2. Grant of Copyright License. Subject to the terms and conditions of this License, each Contributor
hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare, publicly display, publicly perform, sublicense, and distribute the
Complementary Material, the Model, and Derivatives of the Model.

3. Grant of Patent License. Subject to the terms and conditions of this License and where and as
applicable, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge,
royalty-free, irrevocable (except as stated in this paragraph) patent license to make, have made, use, offer
to sell, sell, import, and otherwise transfer the Model and the Complementary Material, where such
license applies only to those patent claims licensable by such Contributor that are necessarily infringed by
their Contribution(s) alone or by combination of their Contribution(s) with the Model to which such
Contribution(s) was submitted. If You institute patent litigation against any entity (including a cross-claim
or counterclaim in a lawsuit) alleging that the Model and/or Complementary Material or a Contribution
incorporated within the Model and/or Complementary Material constitutes direct or contributory patent
infringement, then any patent licenses granted to You under this License for the Model and/or Work shall
terminate as of the date such litigation is asserted or filed.
Section III: CONDITIONS OF USAGE, DISTRIBUTION AND REDISTRIBUTION

4. Distribution and Redistribution. You may host for Third Party remote access purposes (e.g.
software-as-a-service), reproduce and distribute copies of the Model or Derivatives of the Model thereof
in any medium, with or without modifications, provided that You meet the following conditions:

a. Use-based restrictions as referenced in paragraph 5 MUST be included as an enforceable provision
by You in any type of legal agreement (e.g. a license) governing the use and/or distribution of the
Model or Derivatives of the Model, and You shall give notice to subsequent users You Distribute to,
that the Model or Derivatives of the Model are subject to paragraph 5. This provision does not apply
to the use of Complementary Material.

b. You must give any Third Party recipients of the Model or Derivatives of the Model a copy of this
License;

c. You must cause any modified files to carry prominent notices stating that You changed the files;

d. You must retain all copyright, patent, trademark, and attribution notices excluding those notices
that do not pertain to any part of the Model, Derivatives of the Model.
You may add Your own copyright statement to Your modifications and may provide additional or
different license terms and conditions - respecting paragraph 4.a.
- for use, reproduction, or Distribution
of Your modifications, or for any such Derivatives of the Model as a whole, provided Your use,
reproduction, and Distribution of the Model otherwise complies with the conditions stated in this License.

5. Use-based restrictions. The restrictions set forth in Attachment A are considered Use-based restrictions.
Therefore You cannot use the Model and the Derivatives of the Model for the specified restricted uses. You
may use the Model subject to this License, including only for lawful purposes and in accordance with the
License. Use may include creating any content with, finetuning, updating, running, training, evaluating and/or
reparametrizing the Model. You shall require all of Your users who use the Model or a Derivative of the Model
to comply with the terms of this paragraph (paragraph 5).

6. The Output You Generate. Except as set forth herein, Licensor claims no rights in the Output You
generate using the Model. You are accountable for the Output you generate and its subsequent uses. No
use of the output can contravene any provision as stated in the License.

Section IV: OTHER PROVISIONS

7. Updates and Runtime Restrictions. To the maximum extent permitted by law, Licensor reserves the
right to restrict (remotely or otherwise) usage of the Model in violation of this License, update the Model
through electronic means, or modify the Output of the Model based on updates. You shall undertake
reasonable efforts to use the latest version of the Model.

8. Trademarks and related. Nothing in this License permits You to make use of Licensors’ trademarks,
trade names, logos or to otherwise suggest endorsement or misrepresent the relationship between the
parties; and any rights not expressly granted herein are reserved by the Licensors.

9. Disclaimer of Warranty. Unless required by applicable law or agreed to in writing, Licensor provides
the Model and the Complementary Material (and each Contributor provides its Contributions) on an "AS
IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied,
including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT,
MERCHANTABILITY , or FITNESS FOR A PARTICULAR PURPOSE. You are solely responsible for
determining the appropriateness of using or redistributing the Model, Derivatives of the Model, and the
Complementary Material and assume any risks associated with Your exercise of permissions under this
License.

10. Limitation of Liability. In no event and under no legal theory, whether in tort (including negligence),
contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or
agreed to in writing, shall any Contributor be liable to You for damages, including any direct, indirect,
special, incidental, or consequential damages of any character arising as a result of this License or out of
the use or inability to use the Model and the Complementary Material (including but not limited to
damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other
commercial damages or losses), even if such Contributor has been advised of the possibility of such
damages.

11. Accepting Warranty or Additional Liability. While redistributing the Model, Derivatives of the
Model and the Complementary Material thereof, You may choose to offer, and charge a fee for, acceptance
of support, warranty, indemnity, or other liability obligations and/or rights consistent with this License.
However, in accepting such obligations, You may act only on Your own behalf and on Your sole
responsibility, not on behalf of any other Contributor, and only if You agree to indemnify, defend, and
hold each Contributor harmless for any liability incurred by, or claims asserted against, such Contributor
by reason of your accepting any such warranty or additional liability.

12. If any provision of this License is held to be invalid, illegal or unenforceable, the remaining
provisions shall be unaffected thereby and remain valid as if such provision had not been set forth herein.

END OF TERMS AND CONDITIONS

Attachment A

Use Restrictions

You agree not to use the Model or Derivatives of the Model:
(a) In any way that violates any applicable national, federal, state, local or international law
or regulation;
(b) For the purpose of exploiting, harming or attempting to exploit or harm minors in any
way;
(c) To generate or disseminate verifiably false information and/or content with the purpose of
harming others;
(d) To generate or disseminate personal identifiable information that can be used to harm an
individual;
(e) To generate or disseminate information and/or content (e.g. images, code, posts, articles),
and place the information and/or content in any context (e.g. bot generating tweets)
without expressly and intelligibly disclaiming that the information and/or content is
machine generated;
(f) To defame, disparage or otherwise harass others;
(g) To impersonate or attempt to impersonate (e.g. deepfakes) others without their consent;
(h) For fully automated decision making that adversely impacts an individual’s legal rights or
otherwise creates or modifies a binding, enforceable obligation;
(i) For any use intended to or which has the effect of discriminating against or harming
individuals or groups based on online or offline social behavior or known or predicted
personal or personality characteristics;
(j) To exploit any of the vulnerabilities of a specific group of persons based on their age,
social, physical or mental characteristics, in order to materially distort the behavior of a
person pertaining to that group in a manner that causes or is likely to cause that person or
another person physical or psychological harm;
(k) For any use intended to or which has the effect of discriminating against individuals or
groups based on legally protected characteristics or categories;
(l) To provide medical advice and medical results interpretation;
(m) To generate or disseminate information for the purpose to be used for administration of
justice, law enforcement, immigration or asylum processes, such as predicting an
individual will commit fraud/crime commitment (e.g. by text profiling, drawing causal
relationships between assertions made in documents, indiscriminate and
arbitrarily-targeted use).
Article 11

Changes to Terms

The operator may update these Terms as necessary. Updated Terms take effect when posted within the Service or communicated by other means deemed appropriate by the operator.

If a user does not agree to the updated Terms, they should discontinue use of the Service and proceed with account deletion or other applicable procedures.

Article 12

Governing Law and Jurisdiction

These Terms are governed by and construed in accordance with the laws of Japan. In the event of a dispute arising from the Service, the court having jurisdiction over the operator's location shall have exclusive jurisdiction as the court of first instance.