# General Translation Python SDKs: t
URL: https://generaltranslation.com/en-US/docs/python/reference/functions/t.mdx
Docs index: https://generaltranslation.com/llms.txt
Description: Translate and interpolate an ICU MessageFormat string with General Translation in Python. API reference for t.

Translates and interpolates an ICU MessageFormat string into the active request locale. `t` is the primary user-facing translation function.

## Overview [#overview]

Call `t` with a source string and any interpolation variables as keyword arguments. It returns the translated, interpolated string for the current locale, falling back to the interpolated source when no translation is found.

```python
from gt_flask import t  # or: from gt_fastapi import t, or: from gt_i18n import t

message = t("Hello, {name}!", name="World")
```

Signature:

```python
t(message: str, **kwargs: object) -> str
```

*Note: `t` reads the active manager, so [`initialize_gt`](/docs/python/reference/functions/initialize-gt) (or [`set_i18n_manager`](/docs/python/reference/functions/set-i18n-manager)) must run first. Otherwise it raises `RuntimeError`.*

## How it works [#how-it-works]

- **Locale check.** It reads the current locale from the manager. If that locale does not require translation (for example, it matches the default locale), it skips the lookup and only interpolates the source.
- **Hash lookup.** Otherwise it hashes the message (with `_context`, `_id`, and `_max_chars`) and reads the cached translation for the locale from the in-memory cache. The cache is synchronous, so a translation must already be loaded — see [eager loading](/docs/python/guides/configuring#preload).
- **Interpolation.** A found translation is interpolated with ICU MessageFormat, using your variables and the source as a `__fallback` for resolving declared `_gt_` variables.
- **Fallback.** If no translation is found, it interpolates and returns the source string.

## Parameters [#parameters]

| Parameter | Description | Type | Optional | Default |
| --- | --- | --- | --- | --- |
| [`message`](#message) | The ICU MessageFormat source string. | `str` | No | — |
| [`kwargs`](#kwargs) | Interpolation variables and reserved GT options. | keyword args | Yes | — |

### `message` [#message]

**Type** `str` · **Required**

The ICU MessageFormat source string to translate and interpolate.

### `kwargs` [#kwargs]

**Type** keyword arguments · **Optional**

Interpolation variables matching the ICU placeholders, plus these reserved GT options, which are filtered out of interpolation and folded into the message hash:

- `_context` (`str`) — additional context to disambiguate translations with the same source text.
- `_id` (`str`) — a custom identifier for the translation entry.
- `_max_chars` (`int`) — maximum character length applied to the output.

*A user variable whose name starts with a single underscore (for example, `_name`) is still treated as an interpolation variable; only the three keys above are reserved.*

## Returns [#returns]

**Type** `str`

The translated and interpolated string, or the interpolated source when no translation is available.

## Examples [#examples]

```python
# Simple translation
t("Hello, world!")
```

```python
# With variables
t("Hello, {name}!", name="Alice")
```

```python
# With context to disambiguate identical source text
t("Bank", _context="financial institution")
t("Bank", _context="river bank")
```

```python
# With f-strings and declare_var — wrap dynamic values so they are preserved
from gt_flask import t, declare_var

# Before i18n:
message = f"{name} goes home"

# After i18n — wrap with t() and declare_var():
message = t(f"{declare_var(name, name='name')} goes home")
```

```python
# With a character limit
t("This is a very long message that might need truncation", _max_chars=20)
```

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