```properties
supported.languages=ar,bg,bn,ca,ckb_IQ,cs,da,de,el,en_IE,en,es,et,eu,fa,fi,fr,gl,gu,he,hi,hr,hu,hy,id,it,ja,ko,lt,lv,mk,ml,nl,no,pa,pl,pt_BR,pt,ro,ru,si,sq,sv,ta,te,th,tl,tr,uk,ur,vi,zh_CN,zh_TW,zh
```

**Optional configurations:**

If you create online help documentation:
```properties
online.help.supported.langs=ja,sv  # Add your language
```

If you have forum support:
```properties

        value = "zh";
        assertEquals("zh", systemHelper.normalizeLang(value));

        value = "zh-cn";
        assertEquals("zh_CN", systemHelper.normalizeLang(value));

        value = "zh_CN";
        assertEquals("zh_CN", systemHelper.normalizeLang(value));

        value = "zh-tw";
        assertEquals("zh_TW", systemHelper.normalizeLang(value));

        value = "zh_TW";

        assertArrays(new String[] { "ja", "zh-cn" }, fessConfig.normalizeQueryLanguages(new String[] { "ja", "zh" }));
        assertArrays(new String[] { "ja", "zh-cn" }, fessConfig.normalizeQueryLanguages(new String[] { "ja", "zh_CN" }));
        assertArrays(new String[] { "ja", "zh-cn" }, fessConfig.normalizeQueryLanguages(new String[] { "ja", "zh-cn" }));

supported.uploaded.files=license.properties
# Supported languages.
supported.languages=ar,bg,bn,ca,ckb_IQ,cs,da,de,el,en_IE,en,es,et,eu,fa,fi,fr,gl,gu,he,hi,hr,hu,hy,id,it,ja,ko,lt,lv,mk,ml,nl,no,pa,pl,pt_BR,pt,ro,ru,si,sq,sv,ta,te,th,tl,tr,uk,ur,vi,zh_CN,zh_TW,zh
# Length of API access token.
api.access.token.length=60
# Whether API access token is required.
api.access.token.required=false
# API access token request parameter.
api.access.token.request.parameter=

    /** The key of the configuration. e.g. ar,bg,bn,ca,ckb_IQ,cs,da,de,el,en_IE,en,es,et,eu,fa,fi,fr,gl,gu,he,hi,hr,hu,hy,id,it,ja,ko,lt,lv,mk,ml,nl,no,pa,pl,pt_BR,pt,ro,ru,si,sq,sv,ta,te,th,tl,tr,uk,ur,vi,zh_CN,zh_TW,zh */
    String SUPPORTED_LANGUAGES = "supported.languages";

    /** The key of the configuration. e.g. 60 */
    String API_ACCESS_TOKEN_LENGTH = "api.access.token.length";