App Store Localization for Vietnamese: Storefronts, Bytes, Keywords

Apple's localizations table never names Vietnamese as a default language. It appears as an additional language in 2 more: United States and Vietnam. The default language listed next to it is English (US) in one and English (U.K.) in one.

Apple's keyword reference allows 100 bytes, not 100 characters. Counted as UTF-8, the example below contains 45 one-byte, 5 two-byte and 8 three-byte characters (separators excluded). At three bytes a character the field holds at most 33 characters of keywords, commas included. The words below are a hypothetical keyword list for a habit tracker called Streakly; they are illustrations, not validated search terms, and each has at least three characters.

Joined with commas and no spaces after them, the field is:

thói quen,nhắc nhở,mục tiêu,động lực,kỷ luật,lịch trình,theo dõi

That is 64 characters and 85 bytes: 79 bytes of keywords plus 6 commas, leaving 15 of the 100 bytes free. The byte counts assume UTF-8; confirm the final count in App Store Connect before you save.

In Vietnam, English (U.K.) is the default and Vietnamese the only addition. In the United States, English (U.S.) is the default and Vietnamese is the last of nine additional languages, after Arabic, Chinese (Simplified), Chinese (Traditional), French, Korean, Portuguese (Brazil), Russian and Spanish (Mexico). See the Vietnam keyword page.

The locale code Apple gives is vi.

Vietnamese letters can carry two marks at once, such as the circumflex and the dot below in ệ. Precomposed letters like ệ take three bytes, ă and ơ take two, and plain ASCII letters take one. The example table counts the precomposed form. If your text is stored with the marks as separate code points instead, the count rises, so check the byte count in App Store Connect after pasting.

Vietnamese words are written with spaces between syllables. Apple allows spaces inside a keyword phrase but does not document how it treats Vietnamese syllables, so test whether a phrase such as thói quen is better as a phrase or as two separate keywords. Compare the byte profile of Thai.

LocalASO checks keywords in 52 App Store storefronts, each in the storefront's local language, so you can compare your Vietnamese candidates with the English ones in one place. Keywords, ranks and listings stay in a database on your Mac. LocalASO is a one-time $29 purchase and the app needs a license key to run; the setup is in the localization docs and the price is on the pricing page. To test the field you just built, use the keyword field checker, or browse every language page. Related languages: Thai, Indonesian, English (U.S.).