> ## Documentation Index
> Fetch the complete documentation index at: https://developers.deepl.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How to Apply Customizations to Language Variants

> Learn how to apply glossaries and style rules when translating into language variants like FR-CA or EN-GB.

DeepL supports regional language variants such as `PT-BR` vs `PT-PT`, or `FR-CA` vs `FR-FR`. When applying customizations like glossaries and style rules, customizations must be created using the root language code, but can be applied to any variant of that language.

**This guide shows you:**

* How to create customizations using root language codes (e.g. `PT`, `FR`)
* How to pass a customization when translating into a variant target (e.g. `pt-BR`, `fr-CA`)
* A practical example of using variant-specific glossaries to enforce locale-appropriate terminology

## Creating a customization for a language

DeepL distinguishes between root language codes (e.g. `pt`) and language variant codes (e.g. `pt-BR`). Customizations like glossaries and style rules must be created with the root code. Attempting to create one with a variant code will fail.

| **Use this** | **Not this**         |
| :----------- | :------------------- |
| `zh`         | `zh-Hant`, `zh-Hans` |
| `pt`         | `pt-BR`, `pt-PT`     |
| `fr`         | `fr-CA`, `fr-CH`     |
| `de`         | `de-CH`              |
| `it`         | `it-CH`              |
| `es`         | `es-ES`, `es-419`    |

See [supported languages](/docs/getting-started/supported-languages) for the full list.

The following example creates two glossaries to enforce different terms for "invoice" in Brazilian and European Portuguese. Both use the root language code `PT`:

```python Example: Create glossaries with root language codes theme={null}
import deepl

translator = deepl.Translator("YOUR_AUTH_KEY")

glossary_br = translator.create_glossary(
    "PT-BR Invoice Glossary",
    source_lang="EN",
    target_lang="PT",        # root code — not PT-BR
    entries={"invoice": "nota fiscal"}
)

glossary_pt = translator.create_glossary(
    "PT-PT Invoice Glossary",
    source_lang="EN",
    target_lang="PT",        # root code — not PT-PT
    entries={"invoice": "fatura"}
)
```

## Applying a customization to a language variant

Once a customization is created with a root language code, pass its ID in the `/translate` call with a variant `target_lang`:

```python Example: Apply glossaries to variant targets theme={null}
result_br = translator.translate_text(
    "Your invoice is ready to view.",
    source_lang="EN",
    target_lang="PT-BR",
    glossary=glossary_br.glossary_id
)

result_pt = translator.translate_text(
    "Your invoice is ready to view.",
    source_lang="EN",
    target_lang="PT-PT",
    glossary=glossary_pt.glossary_id
)

print(result_br.text)  # Sua nota fiscal está pronta para ser visualizada.
print(result_pt.text)  # A sua fatura está pronta a ser visualizada.
```

## CAT tools

Some CAT tools may prevent applying a glossary or style rule linked to a root code language when the target language is a variant. This is an incorrect limitation that does not reflect the DeepL API's behavior. You'll need to reach out to your CAT tool provider to request this restriction is removed.

***

## Next steps

* **Apply glossaries in practice:** See [Glossaries in the real world](/docs/learning-how-tos/examples-and-guides/glossaries-in-the-real-world) for a full worked example
* **Translate between variants:** Learn about the Write API and style rules in [How to translate between language variants](/docs/learning-how-tos/examples-and-guides/translating-between-variants)
* **Manage style rules:** Explore the [style rules API reference](/api-reference/style-rules) to create and retrieve style rules
* **Improve translation quality:** See how [the context parameter](/docs/learning-how-tos/examples-and-guides/how-to-use-context-parameter) can further refine your translations