---
title: "Language hints"
section: "Concepts"
order: 2
sidebarLabel: "Language hints"
---

Pinch uses **language codes** (like `en-US`, `es-ES`) to decide:

- what language you’re speaking (**source_language**)
- what language you want to hear back (**target_language**)

By default, languages are set to:

- `source_language = "en-US"` (English)
- `target_language = "es-ES"` (Spanish)

So you don’t *have* to choose anything to get started. But when you’re building your own use case, changing these two parameters is the main way you control language behavior.

---

## Where to change the language

```python
await client.translate_file(
    source_language="en-US",  # default
    target_language="es-ES",  # default
)
```
---

## How to pick the right language code

The API expects **valid language codes**, not names.

Use the **Supported languages and codes** tables:

- Input language codes → valid for `source_language`
- Output language codes → valid for `target_language`

See [Supported languages and codes >](/docs/supported-languages) for the full tables.