diff --git a/src/i18n/locales/cs-CZ.json b/src/i18n/locales/cs-CZ.json
index 650c68e89..a4277fd95 100644
--- a/src/i18n/locales/cs-CZ.json
+++ b/src/i18n/locales/cs-CZ.json
@@ -37,6 +37,10 @@
         "time-duration-tooltip": "Video duration",
         "duration-aria": "Duration",
         "time-aria": "Current time",
+        "mutebutton-tooltip": "Mute video",
+        "unmutebutton-tooltip": "Unmute video",
+        "volume-tooltip": "Adjust volume: {{current}}%",
+        "volumeSlider-aria": "Adjust the volume level of the video.",
         "comError-text": "A problem occurred during communication with Opencast.",
         "loadError-text": "An error has occurred loading this video.",
         "durationError-text": "Opencast failed to provide the video duration.",
diff --git a/src/i18n/locales/de-DE.json b/src/i18n/locales/de-DE.json
index 4f8d3a6e6..4f850368c 100644
--- a/src/i18n/locales/de-DE.json
+++ b/src/i18n/locales/de-DE.json
@@ -37,10 +37,10 @@
         "time-duration-tooltip": "Videodauer",
         "duration-aria": "Dauer",
         "time-aria": "Aktuelle Zeit",
-        "mutebutton-tooltip": "Video stummschalten",
-        "unmutebutton-tooltip": "Stummschaltung aufheben",
-        "volume-tooltip": "Lautstärke: {{current}}%",
-        "volumeSlider-aria": "Anpassen der Videolautstärke.",
+        "mutebutton-tooltip": "Mute video",
+        "unmutebutton-tooltip": "Unmute video",
+        "volume-tooltip": "Adjust volume: {{current}}%",
+        "volumeSlider-aria": "Adjust the volume level of the video.",
         "comError-text": "Bei der Kommunikation mit Opencast ist ein Problem aufgetreten.",
         "loadError-text": "Beim Laden des Videos ist ein Fehler aufgetreten.",
         "durationError-text": "Opencast konnte die Video-Dauer nicht angeben.",
diff --git a/src/i18n/locales/el-GR.json b/src/i18n/locales/el-GR.json
index 4f82b4521..124ff2bff 100644
--- a/src/i18n/locales/el-GR.json
+++ b/src/i18n/locales/el-GR.json
@@ -37,6 +37,10 @@
         "time-duration-tooltip": "Διάρκεια βίντεο",
         "duration-aria": "Διάρκεια",
         "time-aria": "Τρέχουσα ώρα",
+        "mutebutton-tooltip": "Mute video",
+        "unmutebutton-tooltip": "Unmute video",
+        "volume-tooltip": "Adjust volume: {{current}}%",
+        "volumeSlider-aria": "Adjust the volume level of the video.",
         "comError-text": "Προέκυψε πρόβλημα κατά την επικοινωνία με το Opencast.",
         "loadError-text": "Παρουσιάστηκε σφάλμα κατά τηn φόρτωση του βίντεο.",
         "durationError-text": "Opencast failed to provide the video duration.",
diff --git a/src/i18n/locales/es-ES.json b/src/i18n/locales/es-ES.json
index 861087f15..9497ea9e6 100644
--- a/src/i18n/locales/es-ES.json
+++ b/src/i18n/locales/es-ES.json
@@ -37,6 +37,10 @@
         "time-duration-tooltip": "Duración del vídeo",
         "duration-aria": "Duración",
         "time-aria": "Tiempo actual",
+        "mutebutton-tooltip": "Mute video",
+        "unmutebutton-tooltip": "Unmute video",
+        "volume-tooltip": "Adjust volume: {{current}}%",
+        "volumeSlider-aria": "Adjust the volume level of the video.",
         "comError-text": "Se ha producido un error al establecer comunicación con Opencast.",
         "loadError-text": "Ocurrió un error al cargar el video.",
         "durationError-text": "Opencast falló al proporcionar la duracion del vídeo.",
diff --git a/src/i18n/locales/fr-FR.json b/src/i18n/locales/fr-FR.json
index 2ad8199c7..32ae19a47 100644
--- a/src/i18n/locales/fr-FR.json
+++ b/src/i18n/locales/fr-FR.json
@@ -37,6 +37,10 @@
         "time-duration-tooltip": "Video duration",
         "duration-aria": "Durée",
         "time-aria": "Temps actuel",
+        "mutebutton-tooltip": "Mute video",
+        "unmutebutton-tooltip": "Unmute video",
+        "volume-tooltip": "Adjust volume: {{current}}%",
+        "volumeSlider-aria": "Adjust the volume level of the video.",
         "comError-text": "Un problème est survenu lors de la communication avec Opencast.",
         "loadError-text": "Une erreur s'est produite lors du chargement de cette vidéo.",
         "durationError-text": "Opencast failed to provide the video duration.",
diff --git a/src/i18n/locales/nl-NL.json b/src/i18n/locales/nl-NL.json
index d8c442d61..67bb8bf69 100644
--- a/src/i18n/locales/nl-NL.json
+++ b/src/i18n/locales/nl-NL.json
@@ -37,6 +37,10 @@
         "time-duration-tooltip": "Video duration",
         "duration-aria": "Duur",
         "time-aria": "Actuele tijd",
+        "mutebutton-tooltip": "Mute video",
+        "unmutebutton-tooltip": "Unmute video",
+        "volume-tooltip": "Adjust volume: {{current}}%",
+        "volumeSlider-aria": "Adjust the volume level of the video.",
         "comError-text": "Er is een probleem opgetreden tijdens de communicatie met Opencast.",
         "loadError-text": "Er is een fout opgetreden tijdens het laden van deze video.",
         "durationError-text": "Opencast failed to provide the video duration.",
diff --git a/src/i18n/locales/zh-CN.json b/src/i18n/locales/zh-CN.json
index 084532152..bd34419f5 100644
--- a/src/i18n/locales/zh-CN.json
+++ b/src/i18n/locales/zh-CN.json
@@ -37,6 +37,10 @@
         "time-duration-tooltip": "Video duration",
         "duration-aria": "Duration",
         "time-aria": "Current time",
+        "mutebutton-tooltip": "Mute video",
+        "unmutebutton-tooltip": "Unmute video",
+        "volume-tooltip": "Adjust volume: {{current}}%",
+        "volumeSlider-aria": "Adjust the volume level of the video.",
         "comError-text": "A problem occurred during communication with Opencast.",
         "loadError-text": "An error has occurred loading this video.",
         "durationError-text": "Opencast failed to provide the video duration.",
diff --git a/src/i18n/locales/zh-TW.json b/src/i18n/locales/zh-TW.json
index 807779ab7..eb2b2cf94 100644
--- a/src/i18n/locales/zh-TW.json
+++ b/src/i18n/locales/zh-TW.json
@@ -37,6 +37,10 @@
         "time-duration-tooltip": "Video duration",
         "duration-aria": "持續時間",
         "time-aria": "目前時間",
+        "mutebutton-tooltip": "Mute video",
+        "unmutebutton-tooltip": "Unmute video",
+        "volume-tooltip": "Adjust volume: {{current}}%",
+        "volumeSlider-aria": "Adjust the volume level of the video.",
         "comError-text": "與 Opencast 通訊時出現問題。",
         "loadError-text": "載入此影片時出現錯誤。",
         "durationError-text": "Opencast failed to provide the video duration.",