diff --git a/src/things/abstract/creative-work.ts b/src/things/abstract/creative-work.ts
index 5220c68b..b243dd21 100644
--- a/src/things/abstract/creative-work.ts
+++ b/src/things/abstract/creative-work.ts
@@ -12,7 +12,7 @@
  * You should have received a copy of the GNU General Public License along with
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
-import {SCLanguage, SCMetaTranslations, SCTranslations} from '../../general/i18n';
+import {SCLanguageCode, SCMetaTranslations, SCTranslations} from '../../general/i18n';
 import {SCISO8601Date} from '../../general/time';
 import {SCOrganizationWithoutReferences} from '../organization';
 import {SCPersonWithoutReferences} from '../person';
@@ -30,6 +30,12 @@ import {
  */
 export interface SCCreativeWorkWithoutReferences
   extends SCThingWithoutReferences, SCThingThatCanBeOfferedWithoutReferences {
+
+  /**
+   * Languages this creative work is available in
+   */
+  availableLanguages?: SCLanguageCode[];
+
   /**
    * Date the creative work was published
    *
@@ -38,9 +44,11 @@ export interface SCCreativeWorkWithoutReferences
   datePublished?: SCISO8601Date;
 
   /**
-   * List of languages this creative work is written/recorded/... in
+   * Languages this creative work is written/recorded/... in
+   *
+   * @filterable
    */
-  inLanguages?: SCLanguage[];
+  inLanguage?: SCLanguageCode;
 
   /**
    * Keywords of the creative work
@@ -103,9 +111,10 @@ export class SCCreativeWorkMeta
     de: {
       ...SCThingMeta.getInstance<SCThingMeta>().fieldTranslations.de,
       ...SCThingThatCanBeOfferedMeta.getInstance().fieldTranslations.de,
-      authors: 'Authoren',
+      authors: 'Autoren',
+      availableLanguages: 'verfügbare Übersetzungen',
       datePublished: 'Veröffentlichungsdatum',
-      inLanguages: 'verfügbare Übersetzungen',
+      inLanguage: 'Inhaltssprache',
       keywords: 'Schlagwörter',
       publishers: 'Verleger',
     },
@@ -113,8 +122,9 @@ export class SCCreativeWorkMeta
       ...SCThingMeta.getInstance<SCThingMeta>().fieldTranslations.en,
       ...SCThingThatCanBeOfferedMeta.getInstance().fieldTranslations.en,
       authors: 'authors',
+      availableLanguages: 'available languages',
       datePublished: 'release date',
-      inLanguages: 'available Languages',
+      inLanguage: 'content language',
       keywords: 'keywords',
       publishers: 'publishers',
     },
diff --git a/src/translator.ts b/src/translator.ts
index eb311029..92ba540a 100644
--- a/src/translator.ts
+++ b/src/translator.ts
@@ -267,7 +267,7 @@ export class SCThingTranslator {
               return this.deeptranslate((objTranslatedFromCache as any)[key]);
             }
           }
-          const objTranslated = this.translateWholeThingDestructively(clone(obj));
+          const objTranslated = this.translateThingInPlaceDestructively(clone(obj));
           this.cache.putObject(objTranslated);
           this.sourceCache.putObject(thing);
 
diff --git a/test/resources/Book.1.json b/test/resources/Book.1.json
index 2b893e67..67a93484 100644
--- a/test/resources/Book.1.json
+++ b/test/resources/Book.1.json
@@ -21,12 +21,7 @@
         "name": "Symposion Publishing"
       }
     ],
-    "inLanguages": [
-      {
-        "name": "german",
-        "code": "de"
-      }
-    ],
+    "inLanguage": "de",
     "bookEdition": "2., überarb. u. erw. Aufl.",
     "isbn": "3936608776",
     "numberOfPages": 537,