Understanding zh-CN, zh-TW, zh-Hans, and zh-Hant in Multilingual Website Development

In the world of multilingual web development, language codes play a crucial role in delivering content that matches users' linguistic preferences. When building websites that serve Chinese-speaking audiences across different regions, developers often encounter language tags like zh-CN, zh-TW, zh-Hans, and zh-Hant. These codes may appear similar at first glance, but they carry distinct meanings and use cases that impact how content is localized and rendered.

This article explores the differences between these language identifiers, their technical foundations, and best practices for implementing them in modern web applications.

What Are Language Tags and Why Do They Matter?

Language tags are standardized codes used to identify languages and regional variations on the web. Defined by the IETF BCP 47 standard, these tags help browsers, search engines, and assistive technologies understand the language of a webpage. One of the most visible uses is in the HTML lang attribute:

<html lang="zh-CN">

When a browser receives a request, it sends an Accept-Language header indicating the user’s preferred languages. For example:

zh-CN,zh;q=0.9,en;q=0.8,fr;q=0.7,pt;q=0.6,so;q=0.5,de;q=0.4,en-US;q=0.3,ko;q=0.2,ja;q=0.1,zh-TW;q=0.1,und;q=0.1

This header tells the server: “Prefer Simplified Chinese as used in China, but fallback to other variants if needed.” Proper handling of such headers ensures users receive content in their preferred language variant—critical for SEO, accessibility, and user experience.

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Decoding zh-CN and zh-TW

zh-CN – Simplified Chinese (China)

The zh-CN language tag refers to Simplified Chinese as used in mainland China. It combines:

zh: the ISO 639-1 code for Chinese
CN: the ISO 3166-1 country code for China

This variant uses simplified characters, which were officially adopted in mainland China in the 1950s to improve literacy. Websites targeting users in mainland China—such as government portals, e-commerce platforms, or news sites—should use zh-CN.

Example URL:
https://docs.microsoft.com/zh-cn/

zh-TW – Traditional Chinese (Taiwan)

The zh-TW tag represents Traditional Chinese as used in Taiwan. It includes:

zh: Chinese language
TW: Taiwan (Province of China) country code

While also used in Hong Kong (zh-HK) and Macau (zh-MO), zh-TW is the most common tag for traditional character content. Despite using the same script, regional differences exist in vocabulary, formatting, and tone.

For instance:

"Software" is 软件 (ruǎnjiàn) in mainland China but 軟體 (ruǎntǐ) in Taiwan.
Date formats and currency symbols also vary.

Using zh-TW ensures your content aligns with cultural expectations in these markets.

Understanding zh-Hans and zh-Hant

Unlike zh-CN and zh-TW, which specify region-based language variants, zh-Hans and zh-Hant focus solely on script type.

zh-Hans – Simplified Chinese Script

zh-Hans stands for Chinese written in simplified script, regardless of region. The suffix Hans comes from ISO 639-3, where:

Hans = Han (Simplified)
Hant = Han (Traditional)

This means zh-Hans can apply to:

Mainland China (zh-CN)
Singapore (zh-SG)
Malaysia (zh-MY)

All of which use simplified characters.

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zh-Hant – Traditional Chinese Script

Similarly, zh-Hant refers to Chinese written in traditional script, covering:

Taiwan (zh-TW)
Hong Kong (zh-HK)
Macau (zh-MO)

It abstracts away regional differences and focuses only on character form.

Key Difference: Region vs. Script

Focus	Tag Example	Use Case
Region + Script	`zh-CN`, `zh-TW`	Targeting specific countries or regions
Script Only	`zh-Hans`, `zh-Hant`	Serving users across regions with same script

Use zh-CN/zh-TW when regional nuances matter (e.g., marketing, legal content). Use zh-Hans/zh-Hant when you want broader script-level targeting (e.g., documentation, educational platforms).

Browser and System Support

As of now, support for zh-Hans and zh-Hant is limited compared to traditional tags.

Windows 10 and Microsoft Edge fully support zh-Hans and zh-Hant.
Most other operating systems and browsers (including Chrome, Firefox, Safari) still default to zh, zh-CN, or zh-TW.

This means if you rely solely on zh-Hans, some users may not receive the correct language version unless proper fallback logic is implemented.

Best Practices for HTML Language Attributes

When setting the lang attribute in your HTML:

Single Language Site

If your site serves only one version of Chinese:

<html lang="zh">

This is sufficient for general content.

Multi-Language Support

For sites offering both simplified and traditional versions:

<!-- Simplified Chinese -->
<html lang="zh-Hans">

<!-- Traditional Chinese -->
<html lang="zh-Hant">

Or, for region-specific targeting:

<html lang="zh-CN"> <!-- Mainland China -->
<html lang="zh-TW"> <!-- Taiwan -->
<html lang="zh-HK"> <!-- Hong Kong -->

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SEO Implications of Language Tags

Search engines like Google use language tags to:

Index content under the correct language
Serve results to regionally appropriate audiences
Avoid duplicate content penalties across language versions

Using precise tags like zh-CN or zh-Hant helps Google distinguish between different Chinese variants—especially important when content differs significantly by region.

Also, pair language tags with:

<hreflang> attributes in <head> or HTTP headers
Proper sitemaps listing each language version

Example:

<link rel="alternate" hreflang="zh-CN" href="https://example.com/zh-cn/" />
<link rel="alternate" hreflang="zh-TW" href="https://example.com/zh-tw/" />
<link rel="alternate" hreflang="zh-Hans" href="https://example.com/zh-hans/" />
<link rel="alternate" hreflang="zh-Hant" href="https://example.com/zh-hant/" />

Core Keywords Summary

To ensure clarity and SEO effectiveness, this article integrates the following core keywords naturally:

multilingual website development
zh-CN vs zh-TW
zh-Hans and zh-Hant
Chinese language localization
HTML lang attribute
language tags in web development
Accept-Language header
SEO for Chinese websites

These terms reflect high-intent search queries from developers, content strategists, and internationalization specialists.

Frequently Asked Questions (FAQ)

What’s the difference between zh-CN and zh-Hans?

zh-CN specifies Simplified Chinese used in mainland China (including regional conventions), while zh-Hans refers only to the simplified script, regardless of region.

Should I use zh-TW or zh-Hant for Hong Kong users?

While Hong Kong uses traditional characters, it has unique vocabulary and formatting. Use zh-HK if possible. If not, zh-Hant is acceptable for script-level targeting.

Do all browsers support zh-Hans?

No. Only newer systems like Windows 10 and Edge support zh-Hans. Most browsers still rely on zh-CN. Always implement fallback mechanisms.

How does Accept-Language affect language selection?

The Accept-Language header tells your server what language the user prefers. Your backend should match this against available versions and redirect accordingly.

Is it okay to use lang="zh" alone?

Yes—for single-language sites where regional variation isn’t important. But for multilingual or global sites, more specific tags improve accuracy.

Does using correct language tags help SEO?

Absolutely. Proper tags help search engines serve the right version to the right audience, reduce bounce rates, and improve rankings in local results.