diff --git a/lib/shared/messages/create-sub-thread-message-spec.js b/lib/shared/messages/create-sub-thread-message-spec.js
--- a/lib/shared/messages/create-sub-thread-message-spec.js
+++ b/lib/shared/messages/create-sub-thread-message-spec.js
@@ -18,11 +18,11 @@
 import type { ThreadInfo } from '../../types/thread-types';
 import type { RelativeUserInfo } from '../../types/user-types';
 import { ET, type EntityText } from '../../utils/entity-text';
+import { notifTextsForSubthreadCreation } from '../notif-utils';
 import {
   pushTypes,
   type CreateMessageInfoParams,
   type MessageSpec,
-  type NotificationTextsParams,
   type GeneratesNotifsParams,
 } from './message-spec';
 import { assertSingleMessageInfo } from './utils';
@@ -129,20 +129,19 @@
   async notificationTexts(
     messageInfos: $ReadOnlyArray<MessageInfo>,
     threadInfo: ThreadInfo,
-    params: NotificationTextsParams,
   ): Promise<NotifTexts> {
     const messageInfo = assertSingleMessageInfo(messageInfos);
     invariant(
       messageInfo.type === messageTypes.CREATE_SUB_THREAD,
       'messageInfo should be messageTypes.CREATE_SUB_THREAD!',
     );
-    return params.notifTextForSubthreadCreation(
-      messageInfo.creator,
-      messageInfo.childThreadInfo.type,
-      threadInfo,
-      messageInfo.childThreadInfo.name,
-      messageInfo.childThreadInfo.uiName,
-    );
+    return notifTextsForSubthreadCreation({
+      creator: messageInfo.creator,
+      threadType: messageInfo.childThreadInfo.type,
+      parentThreadInfo: threadInfo,
+      childThreadName: messageInfo.childThreadInfo.name,
+      childThreadUIName: messageInfo.childThreadInfo.uiName,
+    });
   },
 
   generatesNotifs: async (
diff --git a/lib/shared/messages/create-thread-message-spec.js b/lib/shared/messages/create-thread-message-spec.js
--- a/lib/shared/messages/create-thread-message-spec.js
+++ b/lib/shared/messages/create-thread-message-spec.js
@@ -20,12 +20,12 @@
   type EntityText,
   pluralizeEntityText,
 } from '../../utils/entity-text';
-import { stringForUser } from '../user-utils';
+import { notifTextsForSubthreadCreation } from '../notif-utils';
+import { threadNoun } from '../thread-utils';
 import {
   pushTypes,
   type CreateMessageInfoParams,
   type MessageSpec,
-  type NotificationTextsParams,
 } from './message-spec';
 import { assertSingleMessageInfo } from './utils';
 
@@ -142,29 +142,36 @@
   async notificationTexts(
     messageInfos: $ReadOnlyArray<MessageInfo>,
     threadInfo: ThreadInfo,
-    params: NotificationTextsParams,
   ): Promise<NotifTexts> {
     const messageInfo = assertSingleMessageInfo(messageInfos);
     invariant(
       messageInfo.type === messageTypes.CREATE_THREAD,
       'messageInfo should be messageTypes.CREATE_THREAD!',
     );
+
+    const threadType = messageInfo.initialThreadState.type;
     const parentThreadInfo = messageInfo.initialThreadState.parentThreadInfo;
+    const threadName = messageInfo.initialThreadState.name;
+
     if (parentThreadInfo) {
-      return params.notifTextForSubthreadCreation(
-        messageInfo.creator,
-        messageInfo.initialThreadState.type,
+      return notifTextsForSubthreadCreation({
+        creator: messageInfo.creator,
+        threadType,
         parentThreadInfo,
-        messageInfo.initialThreadState.name,
-        threadInfo.uiName,
-      );
+        childThreadName: threadName,
+        childThreadUIName: threadInfo.uiName,
+      });
     }
-    const prefix = stringForUser(messageInfo.creator);
-    const body = 'created a new chat';
-    let merged = `${prefix} ${body}`;
-    if (messageInfo.initialThreadState.name) {
-      merged += ` called "${messageInfo.initialThreadState.name}"`;
+
+    const creator = ET.user({ userInfo: messageInfo.creator });
+    const prefix = ET`${creator}`;
+
+    const body = `created a new ${threadNoun(threadType)}`;
+    let merged = ET`${prefix} ${body}`;
+    if (threadName) {
+      merged = ET`${merged} called "${threadName}"`;
     }
+
     return {
       merged,
       body,
diff --git a/lib/shared/messages/message-spec.js b/lib/shared/messages/message-spec.js
--- a/lib/shared/messages/message-spec.js
+++ b/lib/shared/messages/message-spec.js
@@ -11,7 +11,7 @@
 } from '../../types/message-types';
 import type { RawUnsupportedMessageInfo } from '../../types/messages/unsupported';
 import type { NotifTexts } from '../../types/notif-types';
-import type { ThreadInfo, ThreadType } from '../../types/thread-types';
+import type { ThreadInfo } from '../../types/thread-types';
 import type { RelativeUserInfo } from '../../types/user-types';
 import type { EntityText } from '../../utils/entity-text';
 import { type ParserRules } from '../markdown';
@@ -45,13 +45,6 @@
 
 export type NotificationTextsParams = {
   +notifThreadName: (threadInfo: ThreadInfo) => string,
-  +notifTextForSubthreadCreation: (
-    creator: RelativeUserInfo,
-    threadType: ThreadType,
-    parentThreadInfo: ThreadInfo,
-    childThreadName: ?string,
-    childThreadUIName: string,
-  ) => NotifTexts,
   +notificationTexts: (
     messageInfos: $ReadOnlyArray<MessageInfo>,
     threadInfo: ThreadInfo,
diff --git a/lib/shared/notif-utils.js b/lib/shared/notif-utils.js
--- a/lib/shared/notif-utils.js
+++ b/lib/shared/notif-utils.js
@@ -24,7 +24,6 @@
 import { robotextForMessageInfo } from './message-utils';
 import { messageSpecs } from './messages/message-specs';
 import { threadNoun } from './thread-utils';
-import { stringForUser } from './user-utils';
 
 async function notifTextsForMessageInfo(
   messageInfos: MessageInfo[],
@@ -92,29 +91,43 @@
   };
 }
 
-const notifTextForSubthreadCreation = (
-  creator: RelativeUserInfo,
-  threadType: ThreadType,
-  parentThreadInfo: ThreadInfo,
-  childThreadName: ?string,
-  childThreadUIName: string,
-) => {
-  const prefix = stringForUser(creator);
+type NotifTextsForSubthreadCreationInput = {
+  +creator: RelativeUserInfo,
+  +threadType: ThreadType,
+  +parentThreadInfo: ThreadInfo,
+  +childThreadName: ?string,
+  +childThreadUIName: EntityText | string,
+};
+function notifTextsForSubthreadCreation(
+  input: NotifTextsForSubthreadCreationInput,
+): NotifTexts {
+  const {
+    creator,
+    threadType,
+    parentThreadInfo,
+    childThreadName,
+    childThreadUIName,
+  } = input;
+
+  const prefix = ET`${ET.user({ userInfo: creator })}`;
+
   let body = `created a new ${threadNoun(threadType)}`;
   if (parentThreadInfo.name) {
-    body += ` in ${parentThreadInfo.name}`;
+    body = ET`${body} in ${parentThreadInfo.name}`;
   }
-  let merged = `${prefix} ${body}`;
+
+  let merged = ET`${prefix} ${body}`;
   if (childThreadName) {
-    merged += ` called "${childThreadName}"`;
+    merged = ET`${merged} called "${childThreadName}"`;
   }
+
   return {
     merged,
     body,
     title: childThreadUIName,
     prefix,
   };
-};
+}
 
 function notifThreadName(threadInfo: ThreadInfo): string {
   if (threadInfo.name) {
@@ -158,7 +171,6 @@
     threadInfo,
     {
       notifThreadName,
-      notifTextForSubthreadCreation,
       notificationTexts: innerNotificationTexts,
     },
   );
@@ -240,6 +252,7 @@
   notifRobotextForMessageInfo,
   notifTextsForMessageInfo,
   notifTextsForEntryCreationOrEdit,
+  notifTextsForSubthreadCreation,
   notifCollapseKeyForRawMessageInfo,
   mergePrefixIntoBody,
 };