diff --git a/angular.json b/angular.json
index a01348f9a136f5de4bc054c13803727cee986091..c16d8983539e20a1e63b4f47b54c9b3215180a2f 100644
--- a/angular.json
+++ b/angular.json
@@ -23,7 +23,7 @@
             ],
             "styles": [
               "src/styles.scss",
-              "./node_modules/material-design-icons/iconfont/material-icons.css",
+              "./node_modules/material-icons/iconfont/material-icons.css",
               "node_modules/prismjs/themes/prism-okaidia.css",
               "node_modules/prismjs/plugins/line-highlight/prism-line-highlight.css",
               "node_modules/prismjs/plugins/line-numbers/prism-line-numbers.css",
diff --git a/package.json b/package.json
index 5e9dd6689e33f2560deda91d908dfa1af35d393e..e2fd9c6e2b55d1d2f83fb6c1115df94f6578759e 100644
--- a/package.json
+++ b/package.json
@@ -40,7 +40,7 @@
     "is-promise": "^4.0.0",
     "katex": "^0.13.0",
     "mat-color-picker": "^1.4.3",
-    "material-design-icons": "^3.0.1",
+    "material-icons": "^1.10.1",
     "naughty-words": "^1.2.0",
     "ngx-color-picker": "^11.0.0",
     "ngx-joyride": "^2.4.0",
diff --git a/src/app/components/shared/_dialogs/topic-cloud-administration/TopicCloudAdminData.ts b/src/app/components/shared/_dialogs/topic-cloud-administration/TopicCloudAdminData.ts
index e0cc85d7b401aa39ada5ae2dee8264bcbab9d69c..3392f218aaa32ba6f7390ad8cdd64991c025496d 100644
--- a/src/app/components/shared/_dialogs/topic-cloud-administration/TopicCloudAdminData.ts
+++ b/src/app/components/shared/_dialogs/topic-cloud-administration/TopicCloudAdminData.ts
@@ -14,7 +14,8 @@ export enum TopicCloudAdminDataScoringKey {
   summedUpvotes = 'summedUpvotes',
   summedDownvotes = 'summedDownvotes',
   summedVotes = 'summedVotes',
-  cappedSummedVotes = 'cappedSummedVotes'
+  cappedSummedVotes = 'cappedSummedVotes',
+  controversy = 'controversy'
 }
 
 export type TopicCloudAdminDataScoringObject = {
@@ -92,7 +93,8 @@ export const keywordsScoringMinMax: TopicCloudAdminDataScoringPreset = {
   summedUpvotes: { min: -5, max: 5 },
   summedDownvotes: { min: -5, max: 5 },
   summedVotes: { min: -5, max: 5 },
-  cappedSummedVotes: { min: -5, max: 5 }
+  cappedSummedVotes: { min: -5, max: 5 },
+  controversy: { min: -5, max: 5 }
 };
 
 export enum KeywordOrFulltext {
diff --git a/src/app/components/shared/comment-list/comment-list.component.html b/src/app/components/shared/comment-list/comment-list.component.html
index 935914fbac71515d1a92d6fc048b5ea6b79c9c3f..ccd3370b4e788264d58ce0256901e386ac4e1d01 100644
--- a/src/app/components/shared/comment-list/comment-list.component.html
+++ b/src/app/components/shared/comment-list/comment-list.component.html
@@ -145,6 +145,13 @@
       <span [ngClass]="{voteasc: 'down'}[filter.sortType]">{{ 'comment-list.sort-vote-desc' | translate }}</span>
     </button>
 
+    <button mat-menu-item
+            (click)="applySortingByKey('controversy')"
+            aria-labelledby="controversy">
+      <mat-icon [ngClass]="{controversy: 'controversy'}[filter.sortType]">quickreply</mat-icon>
+      <span [ngClass]="{controversy: 'controversy'}[filter.sortType]">{{ 'comment-list.sort-controversy' | translate }}</span>
+    </button>
+
   </mat-menu>
 
   <mat-menu #filterMenu="matMenu"
@@ -171,6 +178,17 @@
           [ngClass]="{bookmark: 'bookmark-icon'}[filter.filterType]">{{ 'comment-list.filter-bookmark' | translate }}</span>
       </button>
 
+      <button mat-menu-item
+              (focus)="hideCommentsList=true"
+              (click)="applyFilterByKey('not_bookmarked')"
+              aria-labelledby="not-bookmark">
+        <mat-icon class="not_bookmarked"
+                  [ngClass]="{not_bookmarked: 'not_bookmarked-icon'}[filter.filterType]">bookmark_border
+        </mat-icon>
+        <span
+          [ngClass]="{not_bookmarked: 'not_bookmarked-icon'}[filter.filterType]">{{ 'comment-list.filter-not_bookmarked' | translate }}</span>
+      </button>
+
       <button mat-menu-item
               (focus)="hideCommentsList=true"
               (click)="applyFilterByKey('answer')"
@@ -324,6 +342,7 @@
   <div id="keyboard_arrow_up">{{'comment-list.a11y-keyboard_arrow_up' | translate}}</div>
   <div id="keyboard_arrow_down">{{'comment-list.a11y-keyboard_arrow_down' | translate}}</div>
   <div id="access_time">{{'comment-list.a11y-access_time' | translate}}</div>
+  <div id="controversy">{{'comment-list.a11y-controversy' | translate}}</div>
   <div id="filter_list">{{'comment-list.a11y-filter_list' | translate}}</div>
   <div id="check_circle">{{'comment-list.a11y-check_circle' | translate}}</div>
   <div id="not_interested">{{'comment-list.a11y-not_interested' | translate}}</div>
@@ -331,6 +350,7 @@
   <div id="moderator">{{'comment-list.a11y-moderator' | translate}}</div>
   <div id="lecturer">{{'comment-list.a11y-lecturer' | translate}}</div>
   <div id="bookmark">{{'comment-list.a11y-bookmark' | translate}}</div>
+  <div id="not-bookmark">{{'comment-list.a11y-not-bookmark' | translate}}</div>
   <div id="beamer_icon">{{'comment-list.a11y-beamer_icon' | translate}}</div>
   <div id="close">{{'comment-list.a11y-close' | translate}}</div>
   <div id="add">{{'comment-list.a11y-add' | translate}}</div>
diff --git a/src/app/components/shared/comment-list/comment-list.component.scss b/src/app/components/shared/comment-list/comment-list.component.scss
index 0406d467b2dcac776f2ed43c287f84adbcf72337..21ba728d218114c0327792448de2642069a127db 100644
--- a/src/app/components/shared/comment-list/comment-list.component.scss
+++ b/src/app/components/shared/comment-list/comment-list.component.scss
@@ -147,7 +147,11 @@ app-comment {
 }
 
 .bookmark-icon {
-  color: var(--red);
+  color: var(--magenta);
+}
+
+.not_bookmarked-icon {
+  color: slategray;
 }
 
 .owner-icon {
@@ -187,6 +191,10 @@ h3 {
   color: var(--red);
 }
 
+.controversy {
+  color: var(--primary);
+}
+
 ::placeholder {
   color: var(--on-surface);
   filter: opacity(0.6);
diff --git a/src/app/components/shared/comment-list/comment-list.filter.ts b/src/app/components/shared/comment-list/comment-list.filter.ts
index 7db173bdae7263c0e9c3f62e6fef819d6dd44a68..886a31b3f08d2d4734ca2e9dc1540d0df57e7330 100644
--- a/src/app/components/shared/comment-list/comment-list.filter.ts
+++ b/src/app/components/shared/comment-list/comment-list.filter.ts
@@ -23,6 +23,7 @@ export enum FilterType {
   wrong = 'wrong',
   ack = 'ack',
   bookmark = 'bookmark',
+  not_bookmarked = 'not_bookmarked',
   moderator = 'moderator',
   lecturer = 'lecturer',
   tag = 'tag',
@@ -38,7 +39,8 @@ export type FilterTypeKey = keyof typeof FilterType;
 export enum SortType {
   voteasc = 'voteasc',
   votedesc = 'votedesc',
-  time = 'time'
+  time = 'time',
+  controversy = 'controversy',
 }
 
 export type SortTypeKey = keyof typeof SortType;
@@ -81,6 +83,19 @@ export class CommentListFilter {
     return new CommentListFilter(JSON.parse(localStorage.getItem(name)));
   }
 
+  static calculateControversy(up = 0, down = 0, normalized = true): number {
+    const summed = up + down;
+    const stretch = 10;
+    if (normalized) {
+      if (summed === 0) {
+        return 0;
+      }
+      return (summed - Math.abs(up - down)) * (1 - stretch / (summed + stretch)) / summed;
+    } else {
+      return (summed - Math.abs(up - down)) * (1 - stretch / (summed + stretch));
+    }
+  }
+
   resetToDefault() {
     this.period = DEFAULT_PERIOD;
     this.fromNow = null;
@@ -209,6 +224,9 @@ export class CommentListFilter {
       case FilterType.bookmark:
         filterFunc = (c) => c.bookmark;
         break;
+      case FilterType.not_bookmarked:
+        filterFunc = (c) => !c.bookmark;
+        break;
       case FilterType.read:
         filterFunc = (c) => c.read;
         break;
@@ -258,6 +276,9 @@ export class CommentListFilter {
       case SortType.time:
         sortFunc = (a, b) => new Date(b.timestamp).getTime() - new Date(a.timestamp).getTime();
         break;
+      case SortType.controversy:
+        sortFunc = (a, b) => CommentListFilter.calculateControversy(b.upvotes, b.downvotes) -
+          CommentListFilter.calculateControversy(a.upvotes, a.downvotes);
     }
     if (sortFunc) {
       comments.sort(sortFunc);
diff --git a/src/app/components/shared/header/header.component.html b/src/app/components/shared/header/header.component.html
index 1cc20c002af187d61cab472283a96e5d63b9ed5c..8382f242f982b91ca719597ff3066dbc955b3030 100644
--- a/src/app/components/shared/header/header.component.html
+++ b/src/app/components/shared/header/header.component.html
@@ -221,7 +221,7 @@
                     tabindex="0"
                     *ngIf="!router.url.endsWith('moderator/comments')"
                     routerLink="quiz">
-              <mat-icon>timer</mat-icon>
+              <mat-icon class="material-icons-outlined">timer</mat-icon>
               <span>{{'header.quiz-now' | translate}}</span>
             </button>
 
diff --git a/src/app/models/export.ts b/src/app/models/export.ts
index 88b6c5ab615ec6a9c6d21495c6278269b20a5408..d57b8063d5beb15194452ec6b6181c1f67fa8dd5 100644
--- a/src/app/models/export.ts
+++ b/src/app/models/export.ts
@@ -148,7 +148,7 @@ export class Export {
     let acked = this.translationPath + '.comment-acked';
     let refused = this.translationPath + '.comment-refused';
     let bookmarked = this.translationPath + '.comment-bookmarked';
-    let notBookmarked = this.translationPath + '.comment-not-bookmarked';
+    let notBookmarked = this.translationPath + '.comment-not_bookmarked';
     const roles: [string, string, string] = [
       this.translationPath + '.comment-user-role-participant',
       this.translationPath + '.comment-user-role-moderator',
diff --git a/src/app/services/util/tag-cloud-data.service.ts b/src/app/services/util/tag-cloud-data.service.ts
index 10e3b1351db3868554c4737f5c9376ad45036411..3ccf5532d0f0caddea5fd7519e12d88cda84164a 100644
--- a/src/app/services/util/tag-cloud-data.service.ts
+++ b/src/app/services/util/tag-cloud-data.service.ts
@@ -369,6 +369,7 @@ export class TagCloudDataService {
       tagData.cachedUpVotes * scorings.summedUpvotes.score +
       tagData.cachedDownVotes * scorings.summedDownvotes.score +
       tagData.cachedVoteCount * scorings.summedVotes.score +
+      CommentListFilter.calculateControversy(tagData.cachedUpVotes, tagData.cachedDownVotes, false) * scorings.controversy.score +
       Math.max(tagData.cachedVoteCount, 0) * scorings.cappedSummedVotes.score;
   }
 
diff --git a/src/app/utils/stopwords.ts b/src/app/utils/stopwords.ts
index 3625f0bda79191aa80709c35f3eecff78516627b..2ab545522864e88145f7016bec60e8412883b45c 100644
--- a/src/app/utils/stopwords.ts
+++ b/src/app/utils/stopwords.ts
@@ -16,6 +16,7 @@ export const stopWords = [
   'z. b.',
   'Zum Beispiel',
   'Beispiel',
+  'Bsp',
   'jede',
   'jeder',
   'jede/r',
@@ -39,10 +40,15 @@ export const stopWords = [
   'Du musst',
   'Das heißt',
   'Denkst du',
+  'Kannst du',
+  'Nochmal',
   'Teste',
   'Falls',
   'Nächstes',
   'Gib',
-  'Guten Tag'
+  'Guten Tag',
+  'Moin',
+  'Satz',
+  'Question'
 ];
 export const superfluousSpecialCharacters = '“”‘’„‚«»‹›『』﹃﹄「」﹁﹂",《》〈〉\'`#&…\\/';
diff --git a/src/assets/i18n/creator/de.json b/src/assets/i18n/creator/de.json
index 5ab98733f48df5b760b628c6d5383ae5e95e8013..25dcbaf2034b778b2a5b920eeba076091c252de2 100644
--- a/src/assets/i18n/creator/de.json
+++ b/src/assets/i18n/creator/de.json
@@ -2,6 +2,7 @@
   "comment-list": {
     "a11y-access_time": "Sortiert Fragen nach der Uhrzeit",
     "a11y-add": "Option eine Frage zu stellen",
+    "a11y-controversy": "Sortiert Fragen nach Kontroversität",
     "a11y-pause": "Stoppt den Fragen -Stream",
     "a11y-play": "Startet den Fragen-Stream",
     "a11y-beamer_icon": "Filtert alle besprochenen Fragen",
@@ -13,6 +14,7 @@
     "a11y-moderator": "Filtert alle Fragen von Moderatoren",
     "a11y-lecturer": "Filtert alle Fragen von Dozenten",
     "a11y-bookmark": "Filtert alle Fragen mit Lesezeichen",
+    "a11y-not-bookmark": "Filtert alle Fragen ohne Lesezeichen",
     "a11y-keyboard_arrow_down": "Sortiert die Fragen nach absteigenden Bewertungen",
     "a11y-keyboard_arrow_up": "Sortiert die Fragen nach aufsteigenden Bewertungen",
     "a11y-not_interested": "Filtert alle verneinten Fragen",
@@ -42,6 +44,7 @@
     "filter-correct": "Bejahte Fragen",
     "filter-favorite": "Vorgemerkt für einen Bonus",
     "filter-bookmark": "Markierte Fragen",
+    "filter-not_bookmarked": "Fragen ohne Markierung",
     "filter-moderator": "Hinweise des Moderators",
     "filter-lecturer": "Ankündigungen",
     "filter-owner": "Meine Fragen",
@@ -55,6 +58,7 @@
     "sort-comments": "Fragen sortieren",
     "sort-vote-asc": "Höchste Bewertung zuerst",
     "sort-vote-desc": "Niedrigste Bewertung zuerst",
+    "sort-controversy": "Kontroverse Fragen zuerst",
     "sort-list-time": "Neueste Frage zuerst",
     "time": "Antichronologisch",
     "vote-asc": "Aufsteigende Bewertungen",
@@ -89,7 +93,7 @@
     "comment-refused": "Moderiert",
     "bookmark": "Lesezeichen",
     "comment-bookmarked": "Ja",
-    "comment-not-bookmarked": "Nein",
+    "comment-not_bookmarked": "Nein",
     "comment-got-favorited": "Der Autor dieser guten Frage freut sich über einen Bonus.",
     "upvotes": "Upvotes",
     "downvotes": "Downvotes",
@@ -472,6 +476,8 @@
     "keyword-scoring-summedVotes-info": "Summe aus den Up- und Downvotes, die auf den Kommentaren mit diesem Schlüsselwort gemacht worden sind",
     "keyword-scoring-cappedSummedVotes": "Summe aller Votes (>= 0)",
     "keyword-scoring-cappedSummedVotes-info": "(Siehe Summe aller Votes). Die Summe kann nicht unter null fallen und wird minimal 0",
+    "keyword-scoring-controversy": "Kontroversität einer Frage",
+    "keyword-scoring-controversy-info": "Bildet eine Punktzahl, die von den Upvotes und Downvotes abhängt.",
     "profanity": "Vulgäre Wörter mit »***« überschreiben",
     "hide-blacklist-words": "Themen aus der Blacklist verbergen",
     "sort-alpha": "Alphabetisch",
diff --git a/src/assets/i18n/creator/en.json b/src/assets/i18n/creator/en.json
index 60c28801b11713fd49a0a3c618bd33032ad62365..23fe04602ebf4d1849f1f8403fc1952f44e79ba9 100644
--- a/src/assets/i18n/creator/en.json
+++ b/src/assets/i18n/creator/en.json
@@ -2,6 +2,7 @@
   "comment-list": {
     "a11y-access_time": "Sorts questions by time",
     "a11y-add": "Option to ask a question or to write a message to the audience",
+    "a11y-controversy": "Sorts questions by controversy",
     "a11y-pause": "Stops question stream",
     "a11y-play": "Starts question stream",
     "a11y-beamer_icon": "Filters all discussed questions",
@@ -13,6 +14,7 @@
     "a11y-moderator": "Filters all moderator questions",
     "a11y-lecturer": "Filters all lecturer questions",
     "a11y-bookmark": "Filters all bookmark questions",
+    "a11y-not-bookmark": "Filters all questions without bookmarks",
     "a11y-keyboard_arrow_down": "Sorts questions by descending votes",
     "a11y-keyboard_arrow_up": "Sorts questions by ascending votes",
     "a11y-not_interested": "Filters all questions marked as wrong",
@@ -37,11 +39,12 @@
     "correct": "Marked as correct",
     "favorite": "Bonus question",
     "filter-answered": "Answered questions",
-    "filter-unanswered": "Unanswered questions",
+    "filter-unanswered": "Not answered",
     "filter-comments": "Filter questions",
     "filter-correct": "Affirmed questions",
     "filter-favorite": "Booked for a bonus",
     "filter-bookmark": "Bookmarked questions",
+    "filter-not_bookmarked": "Not bookmarked",
     "filter-moderator": "Notes from the moderator",
     "filter-lecturer": "Announcements",
     "filter-owner": "My questions",
@@ -55,6 +58,7 @@
     "sort-comments": "Sort questions",
     "sort-vote-asc": "Highest rating first",
     "sort-vote-desc": "Lowest rating first",
+    "sort-controversy": "Controversial questions first",
     "sort-list-time": "Newest question first",
     "time": "Time",
     "unread": "Not discussed",
@@ -90,7 +94,7 @@
     "comment-refused": "Moderated",
     "bookmark": "Bookmark",
     "comment-bookmarked": "Yes",
-    "comment-not-bookmarked": "No",
+    "comment-not_bookmarked": "No",
     "comment-got-favorited": "The author of this good question is happy to receive a bonus.",
     "upvotes": "Upvotes",
     "downvotes": "Downvotes",
@@ -482,6 +486,8 @@
     "keyword-scoring-summedVotes-info": "Sum of the upvotes and downvotes made on the comments with this keyword",
     "keyword-scoring-cappedSummedVotes": "Sum of all votes (>= 0)",
     "keyword-scoring-cappedSummedVotes-info": "(See the sum of all votes). The sum cannot fall below zero and becomes a minimum of 0",
+    "keyword-scoring-controversy": "Controversy of a question",
+    "keyword-scoring-controversy-info": "Forms a score depending on the upvotes and downvotes.",
     "profanity": "Censor profanity",
     "hide-blacklist-words": "Hide blacklist keywords",
     "sort-alpha": "Alphabetically",
diff --git a/src/assets/i18n/demo/demo-en.html b/src/assets/i18n/demo/demo-en.html
index 340b7940dd41f4816b09b5c8cb075dc13d6534b2..ed03d6f9f32f9a7adaa8c8e23ab71e8c28c53bae 100644
--- a/src/assets/i18n/demo/demo-en.html
+++ b/src/assets/i18n/demo/demo-en.html
@@ -142,7 +142,7 @@
     The quick location of specific questions is made possible by search, sort and filter options.
     The full text search also includes the answers.
     Sorting is possible by time and rating.
-    The following filter criteria can be selected: Bonus-awarded, bookmarked, answered, unanswered, and own questions.
+    The following filter criteria can be selected: Bonus-awarded, bookmarked, not bookmarked, answered, unanswered, and own questions.
     By clicking on the tag icon of a question, all questions of this category are displayed.
     By clicking on the user icon of a question, all questions of this user will be displayed.
     This allows you to assess the distribution of questions among the question posers:
diff --git a/src/assets/i18n/home/de.json b/src/assets/i18n/home/de.json
index 2236ca0343bb5af16b0621c571ff47ba052d5cea..833150213f8d04452dca32cf0367bcca680a0162 100644
--- a/src/assets/i18n/home/de.json
+++ b/src/assets/i18n/home/de.json
@@ -348,7 +348,7 @@
     "comment-refused": "Moderiert",
     "bookmark": "Lesezeichen",
     "comment-bookmarked": "Ja",
-    "comment-not-bookmarked": "Nein",
+    "comment-not_bookmarked": "Nein",
     "upvotes": "Upvotes",
     "downvotes": "Downvotes",
     "score": "Score",
diff --git a/src/assets/i18n/home/en.json b/src/assets/i18n/home/en.json
index 4054fefc8381761122d9552345db245c4e1eb5df..d632863905b1f0f56bebbf95e520dbe3a0f536e0 100644
--- a/src/assets/i18n/home/en.json
+++ b/src/assets/i18n/home/en.json
@@ -350,7 +350,7 @@
     "comment-refused": "Moderated",
     "bookmark": "Bookmark",
     "comment-bookmarked": "Yes",
-    "comment-not-bookmarked": "No",
+    "comment-not_bookmarked": "No",
     "upvotes": "Upvotes",
     "downvotes": "Downvotes",
     "score": "Score",
diff --git a/src/assets/i18n/participant/de.json b/src/assets/i18n/participant/de.json
index 8d49dcab77a105e2672f35ed275a4f5527404f43..0530a6077a155c08abfaedeb0fe358dd6237ffdd 100644
--- a/src/assets/i18n/participant/de.json
+++ b/src/assets/i18n/participant/de.json
@@ -2,6 +2,7 @@
   "comment-list": {
     "a11y-access_time": "Sortiert Fragen nach der Uhrzeit",
     "a11y-add": "Option eine Frage zu stellen",
+    "a11y-controversy": "Sortiert Fragen nach Kontroversität",
     "a11y-pause": "Stoppt den Fragen-Stream",
     "a11y-play": "Startet den Fragen-Stream",
     "a11y-beamer_icon": "Filtert alle besprochenen Fragen",
@@ -13,6 +14,7 @@
     "a11y-moderator": "Filtert alle Fragen von Moderatoren",
     "a11y-lecturer": "Filtert alle Fragen von Dozenten",
     "a11y-bookmark": "Filtert alle Fragen mit Lesezeichen",
+    "a11y-not-bookmark": "Filtert alle Fragen ohne Lesezeichen",
     "a11y-keyboard_arrow_down": "Sortiert die Fragen nach absteigenden Bewertungen",
     "a11y-keyboard_arrow_up": "Sortiert die Fragen nach aufsteigenden Bewertungen",
     "a11y-not_interested": "Filtert alle verneinten Fragen",
@@ -44,6 +46,7 @@
     "filter-correct": "Bejahte Fragen",
     "filter-favorite": "Vorgemerkt für einen Bonus",
     "filter-bookmark": "Lesezeichen",
+    "filter-not_bookmarked": "Ohne Lesezeichen",
     "filter-moderator": "Hinweise des Moderators",
     "filter-lecturer": "Ankündigungen",
     "filter-owner": "Meine Fragen",
@@ -56,6 +59,7 @@
     "sort-comments": "Fragen sortieren",
     "sort-vote-asc": "Höchste Bewertung zuerst",
     "sort-vote-desc": "Niedrigste Bewertung zuerst",
+    "sort-controversy": "Kontroverse Fragen zuerst",
     "sort-list-time": "Neueste Frage zuerst",
     "tag": "Kategorie",
     "time": "Zeit",
@@ -91,7 +95,7 @@
     "comment-refused": "Moderiert",
     "bookmark": "Lesezeichen",
     "comment-bookmarked": "Ja",
-    "comment-not-bookmarked": "Nein",
+    "comment-not_bookmarked": "Nein",
     "upvotes": "Upvotes",
     "downvotes": "Downvotes",
     "score": "Score",
@@ -384,6 +388,8 @@
     "keyword-scoring-summedVotes-info": "Summe aus den Up- und Downvotes, die auf den Kommentaren mit diesem Schlüsselwort gemacht worden sind",
     "keyword-scoring-cappedSummedVotes": "Summe aller Votes (>= 0)",
     "keyword-scoring-cappedSummedVotes-info": "(Siehe Summe aller Votes). Die Summe kann nicht unter null fallen und wird minimal 0",
+    "keyword-scoring-controversy": "Kontroversität einer Frage",
+    "keyword-scoring-controversy-info": "Bildet eine Punktzahl, die von den Upvotes und Downvotes abhängt.",
     "profanity": "Vulgäre Wörter mit »***« überschreiben",
     "hide-blacklist-words": "Themen aus der Blacklist verbergen",
     "sort-alpha": "Alphabetisch",
diff --git a/src/assets/i18n/participant/en.json b/src/assets/i18n/participant/en.json
index f8899f26c438ee5bea69d3f20046bc2a15f7fb2e..ee4a93093b347e3e16472b63562fb9f985c5eba2 100644
--- a/src/assets/i18n/participant/en.json
+++ b/src/assets/i18n/participant/en.json
@@ -12,6 +12,7 @@
   "comment-list": {
     "a11y-access_time": "Sorts questions by time",
     "a11y-add": "Option to ask a question",
+    "a11y-controversy": "Sorts questions by controversy",
     "a11y-pause": "Stops question stream",
     "a11y-play": "Starts question stream",
     "a11y-beamer_icon": "Filters all discussed questions",
@@ -23,6 +24,7 @@
     "a11y-moderator": "Filters all moderator questions",
     "a11y-lecturer": "Filters all lecturer questions",
     "a11y-bookmark": "Filters all bookmark questions",
+    "a11y-not-bookmark": "Filters all questions without bookmarks",
     "a11y-keyboard_arrow_down": "Sorts questions by descending votes",
     "a11y-keyboard_arrow_up": "Sorts questions by ascending votes",
     "a11y-not_interested": "Filters all questions marked as wrong",
@@ -49,11 +51,12 @@
     "correct": "Marked as correct",
     "favorite": "Bonus question",
     "filter-answered": "Answered questions",
-    "filter-unanswered": "Unanswered questions",
+    "filter-unanswered": "Not answered",
     "filter-comments": "Filter questions",
     "filter-correct": "Affirmed questions",
     "filter-favorite": "Booked for a bonus",
     "filter-bookmark": "Bookmarked questions",
+    "filter-not_bookmarked": "Not bookmarked",
     "filter-moderator": "Notes from the moderator",
     "filter-lecturer": "Announcements",
     "filter-owner": "My questions",
@@ -66,6 +69,7 @@
     "sort-comments": "Sort questions",
     "sort-vote-asc": "Highest rating first",
     "sort-vote-desc": "Lowest rating first",
+    "sort-controversy": "Controversial questions first",
     "sort-list-time": "Latest question first",
     "tag": "Tag",
     "time": "Time",
@@ -101,7 +105,7 @@
     "comment-refused": "Moderated",
     "bookmark": "Bookmark",
     "comment-bookmarked": "Yes",
-    "comment-not-bookmarked": "No",
+    "comment-not_bookmarked": "No",
     "upvotes": "Upvotes",
     "downvotes": "Downvotes",
     "score": "Score",
@@ -390,6 +394,8 @@
     "keyword-scoring-summedVotes-info": "Sum of the upvotes and downvotes made on the comments with this keyword",
     "keyword-scoring-cappedSummedVotes": "Sum of all votes (>= 0)",
     "keyword-scoring-cappedSummedVotes-info": "(See the sum of all votes). The sum cannot fall below zero and becomes a minimum of 0",
+    "keyword-scoring-controversy": "Controversy of a question",
+    "keyword-scoring-controversy-info": "Forms a score depending on the upvotes and downvotes.",
     "profanity": "Censor profanity",
     "hide-blacklist-words": "Hide blacklist keywords",
     "sort-alpha": "Alphabetically",