9 files changed, 155 insertions, 29 deletions
diff --git a/src/components/interface_language_switcher/interface_language_switcher.vue b/src/components/interface_language_switcher/interface_language_switcher.vue
index 6997f149..c9e7506b 100644
--- a/src/components/interface_language_switcher/interface_language_switcher.vue
+++ b/src/components/interface_language_switcher/interface_language_switcher.vue
@@ -1,21 +1,44 @@
 <template>
-  <div>
-    <label for="interface-language-switcher">
+  <div class="interface-language-switcher">
+    <label>
       {{ promptText }}
     </label>
-    {{ ' ' }}
-    <Select
-      id="interface-language-switcher"
-      v-model="controlledLanguage"
-    >
-      <option
-        v-for="lang in languages"
-        :key="lang.code"
-        :value="lang.code"
+    <ul class="setting-list">
+      <li
+        v-for="index of controlledLanguage.keys()"
+        :key="index"
       >
-        {{ lang.name }}
-      </option>
-    </Select>
+        <label>
+          {{ index === 0 ? $t('settings.primary_language') : $tc('settings.fallback_language', index, { index }) }}
+          <Select
+            class="language-select"
+            :model-value="controlledLanguage[index]"
+            @update:modelValue="val => setLanguageAt(index, val)"
+          >
+            <option
+              v-for="lang in languages"
+              :key="lang.code"
+              :value="lang.code"
+            >
+              {{ lang.name }}
+            </option>
+          </Select>
+        </label>
+        <button
+          v-if="controlledLanguage.length > 1 && index !== 0"
+          class="button-default btn"
+          @click="() => removeLanguageAt(index)"
+        >
+          {{ $t('settings.remove_language') }}
+        </button>
+      </li>
+      <li>
+        <button
+          class="button-default btn"
+          @click="addLanguage"
+        >{{ $t('settings.add_language') }}</button>
+      </li>
+    </ul>
   </div>
 </template>
 
@@ -34,7 +57,7 @@ export default {
       required: true
     },
     language: {
-      type: String,
+      type: [Array, String],
       required: true
     },
     setLanguage: {
@@ -48,7 +71,9 @@ export default {
     },
 
     controlledLanguage: {
-      get: function () { return this.language },
+      get: function () {
+        return Array.isArray(this.language) ? this.language : [this.language]
+      },
       set: function (val) {
         this.setLanguage(val)
       }
@@ -58,7 +83,30 @@ export default {
   methods: {
     getLanguageName (code) {
       return localeService.getLanguageName(code)
+    },
+    addLanguage () {
+      this.controlledLanguage = [...this.controlledLanguage, '']
+    },
+    setLanguageAt (index, val) {
+      const lang = [...this.controlledLanguage]
+      lang[index] = val
+      this.controlledLanguage = lang
+    },
+    removeLanguageAt (index) {
+      const lang = [...this.controlledLanguage]
+      lang.splice(index, 1)
+      this.controlledLanguage = lang
     }
   }
 }
 </script>
+
+<style lang="scss">
+@import '../../_variables.scss';
+
+.interface-language-switcher {
+  .language-select {
+    margin-right: 1em;
+  }
+}
+</style>
diff --git a/src/components/settings_modal/tabs/profile_tab.js b/src/components/settings_modal/tabs/profile_tab.js
index ff2ccef2..b2d8fed2 100644
--- a/src/components/settings_modal/tabs/profile_tab.js
+++ b/src/components/settings_modal/tabs/profile_tab.js
@@ -43,7 +43,7 @@ const ProfileTab = {
       bannerPreview: null,
       background: null,
       backgroundPreview: null,
-      emailLanguage: this.$store.state.users.currentUser.language || ''
+      emailLanguage: this.$store.state.users.currentUser.language || ['']
     }
   },
   components: {
@@ -130,7 +130,7 @@ const ProfileTab = {
       }
 
       if (this.emailLanguage) {
-        params.language = localeService.internalToBackendLocale(this.emailLanguage)
+        params.language = localeService.internalToBackendLocaleMulti(this.emailLanguage)
       }
 
       this.$store.state.api.backendInteractor
diff --git a/src/i18n/en.json b/src/i18n/en.json
index ca022c82..c8de6851 100644
--- a/src/i18n/en.json
+++ b/src/i18n/en.json
@@ -339,6 +339,10 @@
     "select_all": "Select all"
   },
   "settings": {
+    "add_language": "Add fallback language",
+    "remove_language": "Remove",
+    "primary_language": "Primary language:",
+    "fallback_language": "Fallback language {index}:",
     "app_name": "App name",
     "expert_mode": "Show advanced",
     "save": "Save changes",
diff --git a/src/i18n/eo.json b/src/i18n/eo.json
index 3596065c..e013edee 100644
--- a/src/i18n/eo.json
+++ b/src/i18n/eo.json
@@ -603,7 +603,7 @@
     "use_websockets": "Uzi teĥnikaron «websockets» (tuja ĝisdatigo)",
     "mention_link_display_full_for_remote": "plene nur je uzantoj foraj (ekz. {'@'}zozo{'@'}ekzemplo.org)",
     "expert_mode": "Montri altnivelajn",
-    "setting_server_side": "Ĉi tiu agordo estas ligita al via profilo, kaj efektiviĝon en ĉiuj viaj salutoj kaj klientoj",
+    "setting_server_side": "Ĉi tiu agordo estas ligita al via profilo, kaj efektiviĝos en ĉiuj viaj salutoj kaj klientoj",
     "post_look_feel": "Aspekto de afiŝoj",
     "mention_links": "Menciaj ligiloj",
     "email_language": "Lingvo de leteroj ricevotaj de la servilo",
diff --git a/src/i18n/messages.js b/src/i18n/messages.js
index 74a89ca8..849d98fd 100644
--- a/src/i18n/messages.js
+++ b/src/i18n/messages.js
@@ -7,8 +7,11 @@
 // sed -i -e "s/'//gm" -e 's/"/\\"/gm' -re 's/^( +)(.+?): ((.+?))?(,?)(\{?)$/\1"\2": "\4"/gm' -e 's/\"\{\"/{/g' -e 's/,"$/",/g' file.json
 // There's only problem that apostrophe character ' gets replaced by \\ so you have to fix it manually, sorry.
 
+import { isEqual } from 'lodash'
 import { languages, langCodeToJsonName } from './languages.js'
 
+const ULTIMATE_FALLBACK_LOCALE = 'en'
+
 const hasLanguageFile = (code) => languages.includes(code)
 
 const loadLanguageFile = (code) => {
@@ -25,11 +28,26 @@ const messages = {
     en: require('./en.json').default
   },
   setLanguage: async (i18n, language) => {
-    if (hasLanguageFile(language)) {
-      const messages = await loadLanguageFile(language)
-      i18n.setLocaleMessage(language, messages.default)
+    const languages = (Array.isArray(language) ? language : [language]).filter(k => k)
+
+    if (!languages.includes(ULTIMATE_FALLBACK_LOCALE)) {
+      languages.push(ULTIMATE_FALLBACK_LOCALE)
+    }
+    const [first, ...rest] = languages
+
+    if (first === i18n.locale && isEqual(rest, i18n.fallbackLocale)) {
+      return
     }
-    i18n.locale = language
+
+    for (const lang of languages) {
+      if (hasLanguageFile(lang)) {
+        const messages = await loadLanguageFile(lang)
+        i18n.setLocaleMessage(lang, messages.default)
+      }
+    }
+
+    i18n.fallbackLocale = rest
+    i18n.locale = first
   }
 }
 
diff --git a/src/i18n/zh.json b/src/i18n/zh.json
index cf5f384c..8f0b04bd 100644
--- a/src/i18n/zh.json
+++ b/src/i18n/zh.json
@@ -53,7 +53,13 @@
       "direct": "私讯",
       "private": "仅关注者",
       "unlisted": "列外"
-    }
+    },
+    "scroll_to_top": "滚动至顶",
+    "generic_error_message": "发生一个错误：{0}",
+    "never_show_again": "不再显示",
+    "undo": "撤销",
+    "yes": "是",
+    "no": "否"
   },
   "image_cropper": {
     "crop_picture": "裁剪图片",
@@ -109,7 +115,12 @@
     "chats": "聊天",
     "timelines": "时间线",
     "bookmarks": "书签",
-    "home_timeline": "主页时间线"
+    "home_timeline": "主页时间线",
+    "lists": "列表",
+    "edit_finish": "完成编辑",
+    "mobile_notifications": "打开通知（有未读的）",
+    "mobile_notifications_close": "关闭通知",
+    "announcements": "公告"
   },
   "notifications": {
     "broken_favorite": "未知的状态，正在搜索中…",
@@ -890,7 +901,18 @@
     "search_emoji": "搜索表情符号",
     "emoji": "表情符号",
     "load_all": "加载所有表情符号（共 {emojiAmount} 个）",
-    "load_all_hint": "最先加载的 {saneAmount} 表情符号，加载全部表情符号可能会带来性能问题。"
+    "load_all_hint": "最先加载的 {saneAmount} 表情符号，加载全部表情符号可能会带来性能问题。",
+    "unicode_groups": {
+      "flags": "旗帜",
+      "food-and-drink": "饮食",
+      "objects": "物件",
+      "people-and-body": "人和身体",
+      "symbols": "符号",
+      "travel-and-places": "旅行和地点",
+      "activities": "活动",
+      "animals-and-nature": "动物和自然"
+    },
+    "regional_indicator": "地区指示符 {letter}"
   },
   "about": {
     "mrf": {
@@ -958,5 +980,26 @@
     "delete": "删除",
     "message_user": "发消息给 {nickname}",
     "you": "你："
+  },
+  "announcements": {
+    "page_header": "公告",
+    "title": "公告",
+    "mark_as_read_action": "标为已读",
+    "post_form_header": "发布公告",
+    "post_placeholder": "在这里输入公告内容...",
+    "post_action": "发布",
+    "post_error": "错误：{error}",
+    "close_error": "关闭",
+    "delete_action": "删除",
+    "start_time_prompt": "起始时间： ",
+    "end_time_prompt": "终止时间： ",
+    "all_day_prompt": "这是全天的事件",
+    "published_time_display": "发表于 {time}",
+    "start_time_display": "开始于 {time}",
+    "end_time_display": "结束于 {time}",
+    "edit_action": "编辑",
+    "submit_edit_action": "提交",
+    "cancel_edit_action": "取消",
+    "inactive_message": "这个公告不活跃"
   }
 }
diff --git a/src/modules/config.js b/src/modules/config.js
index 8e6b2c3d..eb33f95f 100644
--- a/src/modules/config.js
+++ b/src/modules/config.js
@@ -193,7 +193,10 @@ const config = {
         case 'interfaceLanguage':
           messages.setLanguage(this.getters.i18n, value)
           dispatch('loadUnicodeEmojiData', value)
-          Cookies.set(BACKEND_LANGUAGE_COOKIE_NAME, localeService.internalToBackendLocale(value))
+          Cookies.set(
+            BACKEND_LANGUAGE_COOKIE_NAME,
+            localeService.internalToBackendLocaleMulti(value)
+          )
           break
         case 'thirdColumnMode':
           dispatch('setLayoutWidth', undefined)
diff --git a/src/modules/instance.js b/src/modules/instance.js
index ce958907..c7579162 100644
--- a/src/modules/instance.js
+++ b/src/modules/instance.js
@@ -295,8 +295,13 @@ const instance = {
         langList
           .map(async lang => {
             if (!state.unicodeEmojiAnnotations[lang]) {
-              const annotations = await loadAnnotations(lang)
-              commit('setUnicodeEmojiAnnotations', { lang, annotations })
+              try {
+                const annotations = await loadAnnotations(lang)
+                commit('setUnicodeEmojiAnnotations', { lang, annotations })
+              } catch (e) {
+                console.warn(`Error loading unicode emoji annotations for ${lang}: `, e)
+                // ignore
+              }
             }
           }))
     },
diff --git a/src/services/locale/locale.service.js b/src/services/locale/locale.service.js
index d3389785..a4af8b90 100644
--- a/src/services/locale/locale.service.js
+++ b/src/services/locale/locale.service.js
@@ -11,6 +11,10 @@ const specialLanguageCodes = {
 const internalToBrowserLocale = code => specialLanguageCodes[code] || code
 
 const internalToBackendLocale = code => internalToBrowserLocale(code).replace('_', '-')
+const internalToBackendLocaleMulti = codes => {
+  const langs = Array.isArray(codes) ? codes : [codes]
+  return langs.map(internalToBackendLocale).join(',')
+}
 
 const getLanguageName = (code) => {
   const specialLanguageNames = {
@@ -28,6 +32,7 @@ const languages = _.map(languagesObject.languages, (code) => ({ code, name: getL
 const localeService = {
   internalToBrowserLocale,
   internalToBackendLocale,
+  internalToBackendLocaleMulti,
   languages,
   getLanguageName
 }