What are the correct 'Language' tag values for Traditional and Simplified Chinese?

Chinese is the one exception to the usual Language tag rule. For every other language the Pushwoosh SDK sets the Language tag to a lowercase two-letter ISO-639-1 code (en, de, pt…). For Chinese it sends a script- or region-qualified tag so Simplified and Traditional can be told apart — and the exact value differs by platform.

What each SDK actually sends

• iOS: language code plus script code, i.e. zh-Hans for Simplified Chinese and zh-Hant for Traditional Chinese.
• Android: the device's full BCP-47 language tag for any zh locale. Depending on the device that is zh-Hans-CN, zh-Hant-TW, zh-CN, zh-TW, zh-HK and similar — not a bare zh-Hans / zh-Hant.

(The Hans / Hant parts are ISO 15924 script subtags within BCP 47, not ISO 639 language codes.)

Why this matters

Language matching for multi-language content is an exact string match on the device's Language tag value, with a fallback chain of device language → default → en. So content keyed only on zh-Hant and zh-Hans will reach iOS users but fall back to the default localisation for most Android users.

Recommendations

• Before building a campaign, check which values your own audience actually reports. Open Tags statistics for the Language tag to see the real distribution in your project.
• Add a content variant for every Chinese value present in your base — typically zh-Hans and zh-Hant plus the region/script-qualified Android variants you see.
• Always provide a default localisation so anything unmatched still receives sensible content.
• If you set the Language tag yourself via the API instead of letting the SDK do it, pick one convention and apply it consistently across platforms.