Microsoft Teams custom dictionaries help organizations improve meeting transcription for the words that matter most to them, including product names, acronyms, department language, and industry-specific terms. Setup is straightforward, but there are a few important requirements and limits to understand before rolling it out.
Teach Teams Your Company's Language
If your Teams transcripts have ever mangled a product name, missed an acronym, or turned an industry term into nonsense, you are not alone. Microsoft built custom dictionaries for Teams meetings to solve that exact problem. Teams transcription is powered by AI models trained on general language datasets. That means they can do a great job with everyday conversation, but they might not recognize the specialized language your organization uses every day, like internal acronyms, product names, department shorthand, or industry jargon.
The custom dictionary
A custom dictionary is a company-managed list of terms that you upload to Microsoft 365. Once it is in place, Teams can better recognize those words in qualifying meetings. This feature allows the model to dynamically adapt during meetings and then also performs post-correction once the meeting ends, ensuring accurate transcription of these specialized terms.
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."
Deployment steps
Here are the high-level steps to deploy a dictionary. The full steps to deploy the custom dictionary are documented in Manage custom dictionaries for Microsoft Teams meetings and events - Microsoft Teams | Microsoft Learn.
1. Sign in to the Microsoft 365 admin center with an account that has the AI Administrator role.
2. Go to Copilot > Settings > Copilot Custom Dictionary.
3. Download the CSV template and add your organization’s key terms, acronyms, and jargon.
4. Save the file as CSV UTF-8 and upload it back to the Custom Dictionary page.
5. Choose the correct language for the dictionary.
6. Wait up to 24 hours for the dictionary to become active in supported Teams meetings.
Once deployed, you should update it as your company evolves. You have the option to do a full overwrite of it or update the existing dictionary (incremental). This section covers these details. Manage custom dictionaries for Microsoft Teams meetings and events - Microsoft Teams | Microsoft Learn
Important to Know
License requirement - Users need a Microsoft 365 Copilot license.
Admin role - The person managing the dictionary must have the AI Administrator role.
Supported scenarios - Works for scheduled meetings, webinars, and town halls.
Not supported - 1:1 calls and group calls are not supported.
Activation time - Changes can take up to 24 hours to go live.
Scope - The feature is tenant-wide, supports one dictionary per language, and each dictionary can contain up to 1,000 entries.
It is also worth noting that custom dictionary data is used only within your organization for meetings and is not used for AI model training.
Wrap-Up
Microsoft Teams custom dictionaries are a practical way to make meeting transcription more accurate for the language your business actually uses. If your teams rely on acronyms, specialized terminology, product names, or department-specific shorthand, this feature can make transcripts easier to trust and easier to use.
The setup is simple: prepare a CSV, upload it in the Microsoft 365 admin center, choose the right language, and let it activate. For organizations already using Microsoft 365 Copilot in Teams, this is a straightforward feature that can improve the quality of meeting output without adding any extra work for everyday users.
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