---
title: "[Set Up Your Project] - Set the Master Language"
description: Set the master language for a Contentstack stack and understand limitations and localization options.
url: https://www.contentstack.com/docs/developers/multilingual-content/set-the-master-language
product: Contentstack
doc_type: guide
audience:
  - developers
version: v1
last_updated: 2026-03-25
---

# [Set Up Your Project] - Set the Master Language

This page explains what the master language is in a Contentstack stack, when you set it, and the key limitation that it cannot be changed later. It is intended for developers and content administrators setting up a stack for multilingual content and localization.

## Set the Master Language

Master language is the primary language of your [stack](/docs/developers/set-up-stack/about-stack).

When you [create a stack](/docs/developers/set-up-stack/create-a-new-stack) in Contentstack, you are prompted to set a language as the master language of the stack. Later, you can add other languages for the purpose of localization.

**Warning**: You cannot change the master language of a stack once it has been set.

For example, a Japanese user can set the master language of the stack to “Japanese” and can publish content in Japanese language. The user can later add “English (United States)” or any other language as an additional language, and publish content in these languages, too.

**Additional Resource**: To learn how you can localize an entry, refer to the [Localization](/docs/developers/multilingual-content/about-localization) guide.

## Common questions

### Can I change the master language after creating a stack?
No. **Warning**: You cannot change the master language of a stack once it has been set.

### When do I choose the master language?
When you [create a stack](/docs/developers/set-up-stack/create-a-new-stack) in Contentstack, you are prompted to set a language as the master language of the stack.

### Can I add more languages later for localization?
Yes. Later, you can add other languages for the purpose of localization.

### Where can I learn how to localize an entry?
Refer to the [Localization](/docs/developers/multilingual-content/about-localization) guide.