diff --git a/packages/nicolium/src/features/notifications/components/notification.tsx b/packages/nicolium/src/features/notifications/components/notification.tsx
index 44e067d3f..ed727f9b8 100644
--- a/packages/nicolium/src/features/notifications/components/notification.tsx
+++ b/packages/nicolium/src/features/notifications/components/notification.tsx
@@ -91,6 +91,15 @@ const icons: Partial<Record<NotificationType | 'reply', string>> = {
   quoted_update: require('@phosphor-icons/core/regular/pencil-simple-line.svg'),
 };
 
+// For use by the service worker
+defineMessages({
+  group: {
+    id: 'notifications.group',
+    defaultMessage: '{count, plural, one {# notification} other {# notifications}}',
+  },
+  showMore: { id: 'status.show_more', defaultMessage: 'Show more' },
+});
+
 const messages: Record<NotificationType | 'reply', MessageDescriptor> = defineMessages({
   follow: {
     id: 'notification.follow',
diff --git a/packages/nicolium/src/locales/en.json b/packages/nicolium/src/locales/en.json
index 891386b6b..89fe4b297 100644
--- a/packages/nicolium/src/locales/en.json
+++ b/packages/nicolium/src/locales/en.json
@@ -1530,6 +1530,7 @@
   "notifications.filter.mentions": "Mentions",
   "notifications.filter.polls": "Poll results",
   "notifications.filter.statuses": "Updates from people you follow",
+  "notifications.group": "{count, plural, one {# notification} other {# notifications}}",
   "notifications.queue_label": "Click to see {count} new {count, plural, one {notification} other {notifications}}",
   "notifications.queue_label.live_region": "{count} new {count, plural, one {notification} other {notifications}}.",
   "oauth_consumer.tooltip": "Sign in with {provider}",
@@ -1900,6 +1901,7 @@
   "status.share": "Share",
   "status.show_filter_reason": "Show anyway",
   "status.show_less_all": "Show less for all",
+  "status.show_more": "Show more",
   "status.show_more_all": "Show more for all",
   "status.show_original": "Show original",
   "status.skip_pinned": "Skip pinned posts",
diff --git a/packages/nicolium/src/service-worker/sw.ts b/packages/nicolium/src/service-worker/sw.ts
index 38878370e..25aa1402e 100644
--- a/packages/nicolium/src/service-worker/sw.ts
+++ b/packages/nicolium/src/service-worker/sw.ts
@@ -147,8 +147,10 @@ const cloneNotification = (notification: Notification): ClonedNotification => {
 };
 
 /** Get translated message for the user's locale. */
-const formatMessage = (messageId: string, locale: string, values = {}): string =>
-  new IntlMessageFormat(locales[locale][messageId], locale).format(values) as string;
+const formatMessage = (messageId: string, locale: string, values = {}): string => {
+  const message = locales[locale]?.[messageId] ?? locales['en'][messageId];
+  return new IntlMessageFormat(message, locale).format(values) as string;
+};
 
 /** Strip HTML for display in a native notification. */
 const htmlToPlainText = (html: string): string =>