Manage custom dictionaries for Microsoft Teams meetings and events

Meetings Webinars Town halls

Overview

Organizations often use their own special terms, acronyms, and jargon, like product names, department-specific language, and industry-specific terms. The AI models powering Teams transcription are trained using general datasets that might not recognize these specialized terms. When you import a custom dictionary, the model dynamically adapts during meetings and performs post-correction once the meeting ends, ensuring accurate transcription of these specialized terms.

As an admin, you can upload a custom dictionary in the Microsoft 365 admin center to enhance entity recognition and improve transcription accuracy across Teams meetings and events.

Prerequisites

Admin

You must meet the following requirements to upload and manage custom dictionaries:

• You must have the AI administrator role. To learn more about admin roles, see About admin roles in the Microsoft 365 admin center.

Your users

Users in your organization must meet the following requirements to use custom dictionaries:

• An eligible Microsoft 365 base license.
  • For the list of eligible base licenses, see Understand licensing requirements for Microsoft 365 Copilot.
• An eligible Microsoft Teams license.
  • Teams licenses might be included in your Microsoft 365 subscription, or you might need to purchase a separate Teams license if you have Microsoft 365 (no Teams) licenses.
• A Microsoft 365 Copilot license.
  • For information on how to acquire Microsoft 365 Copilot licenses, see Where can I get Microsoft Copilot?.
• Be a Microsoft Teams Public preview participant.
  • For information on how to access Teams Public preview features, see Microsoft Teams Public preview.

Understand custom dictionaries

The custom dictionary captures organization-specific terminology to improve transcript accuracy and help the AI model better recognize and understand key entities. You upload and manage custom dictionaries manually at the tenant level. This feature doesn't currently support group or user specific dictionaries. Its purpose is to give you a centralized way to maintain terminology for your organization. All meetings and events created by your users in your organization with a Microsoft 365 Copilot license automatically benefit from these terms when used, without any negative impact if they aren't.

Who can update custom dictionaries?

As an admin, you're the only one who can create and update the custom dictionary with new terms from your organization. Uploading a new dictionary replaces the existing one in the same language. Your users can't add terms to the dictionary; they must ask you to upload an updated dictionary with new terms.

Dictionary content

The dictionary is presented in a flat list format, with optional fields for recording the "Sounds like" and "Long form of the term," and a comments section to provide more context. This helps you manage and collect entries from systems or product groups in your organization. Each custom dictionary includes the following columns:

Dictionary sample

The following are examples of dictionary entries. The first column, Term, is the most important and should be mapped to your expected format from the transcription output.

Dictionary file format and language

You should create the dictionary in a CSV plain-text format with UTF-8 encoding and comma-delimited format. We recommend the Excel output format option "CSV UTF-8 (comma delimited)." Each dictionary can contain up to 500 terms/entries. You can upload one dictionary per language, which is applied to the target Teams transcription language(region) setting as described in the following table.

Upload a custom dictionary

Navigate through the Microsoft 365 admin center

1. Sign in to the Microsoft 365 admin center.
2. From the navigation pane, select Copilot, and go to Settings.
3. Under the Name column, select Copilot Custom Dictionary to open the custom dictionary management pane.
4. Select Upload Dictionary.

Create the custom dictionary with a CSV file

5. Select the option to download the CSV template with header only from the portal.
6. Open the template with Excel, open with UTF-8 and comma-delimited format.
7. Fill in your custom terms in the Term (required) column as a flat list.
8. (optional) Fill in additional information in the Sounds like, Long form of the term (for acronyms), and Definition and context columns.
9. Save the file as CSV UTF-8 (Comma delimited) (.csv).

Upload your custom dictionary

10. Return to the uploading view and select your CSV file in the Upload CSV file with terms field.
11. Select the target language for this dictionary, then select Upload.

12. After the loading page, a message appears at the top of the view, indicating if the upload was successful. If successful, your dictionary appears in the dictionary list in the management view.
13. Wait for up to 24 hours for the dictionary to become available for Teams meetings in your organization.

Optimize your custom dictionary

To optimize your custom dictionary, follow these best practices:

• Include frequently mentioned terminology, acronyms, product names, project codes, team names, and industry-specific language relevant to your meetings.
• Allowed symbols in term- Don't include punctuation in the Term column and use fewer symbols. Symbols allowed in the middle of terms are: -'/&·ㆍ.
• Localize dictionaries- To create dictionaries in the corresponding languages, you should collect custom terms from each local group. For example, in the Japanese dictionary, some terms might remain in their English Latin form, while others might have local variants. Include all these terms in the Japanese custom dictionary to benefit meetings where Japanese is the primary language.
• Break down multi-word names- For names with multiple words, consider splitting them into individual parts. For example, instead of "Copilot in Power Platform and Dynamics 365," create separate entries for "Copilot," "Power Platform," and "Dynamics 365."
• Use Copilot for extra fields- Use Copilot to generate entries for Sounds like, Long form of the term (for acronyms), and Definition and context, then review and modify the entries as needed.
• Avoid short words: Avoid using short terms like "AB."
• Avoid numeric terms: Avoid including terms that are purely numeric like "123."
• Avoid repeated chars: Avoid using terms with repeated chars like "AAA."

Data safety

• Custom dictionary should be restricted to tenant-specific terms that are relevant to the tenant's needs and must not contain any confidential, sensitive, or personal information.
• Custom dictionary data is used solely within your organization for meetings. Nobody else accesses the data and it isn't included in any AI model training.

Supported scenarios

Supported

Custom Dictionary enhances entity recognition for Teams transcription in the following scenarios:

• Scheduled meetings
• Town halls
• Webinars

Not supported

Custom Dictionary isn't supported in the following scenarios:

• Group and 1:1 calls

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