diff --git a/app/javascript/mastodon/features/compose/redesign/hints.tsx b/app/javascript/mastodon/features/compose/redesign/hints.tsx
new file mode 100644
index 00000000000..60ae65b6f7a
--- /dev/null
+++ b/app/javascript/mastodon/features/compose/redesign/hints.tsx
@@ -0,0 +1,145 @@
+import type React from 'react';
+import { useCallback } from 'react';
+
+import { FormattedMessage } from 'react-intl';
+
+import { WarningIcon } from '@phosphor-icons/react';
+
+import { changeComposeLanguage } from '@/mastodon/actions/compose';
+import { Callout } from '@/mastodon/components/callout/redesign';
+import { useDismissible } from '@/mastodon/hooks/useDismissible';
+import { selectAccountStatus } from '@/mastodon/selectors/statuses';
+import {
+  createAppSelector,
+  useAppDispatch,
+  useAppSelector,
+} from '@/mastodon/store';
+
+import { useLanguageGuess, useLanguages } from './hooks';
+import { selectComposeAttachments } from './selectors';
+
+const selectComposeAttachmentsWithoutAlt = createAppSelector(
+  [selectComposeAttachments],
+  (attachments) => ({
+    count: attachments.length,
+    missingAlt: attachments.some((attachment) => !attachment.description),
+  }),
+);
+
+const selectIsFollowersReply = createAppSelector(
+  [
+    (state) =>
+      selectAccountStatus(
+        state,
+        state.compose.get('in_reply_to') as null | string,
+      ),
+  ],
+  (status) => (status?.visibility === 'private' ? status.account.acct : null),
+);
+
+export const ComposeHints = () => {
+  const { count, missingAlt } = useAppSelector(
+    selectComposeAttachmentsWithoutAlt,
+  );
+  const replyFollowersHandle = useAppSelector(selectIsFollowersReply);
+
+  const lang = useAppSelector(
+    (state) => state.compose.get('language') as string,
+  );
+  const guess = useLanguageGuess();
+  const isDifferentLanguage = lang && guess && lang !== guess;
+
+  const messages: React.ReactNode[] = [];
+
+  if (replyFollowersHandle) {
+    messages.push(
+      defaultWrapper(
+        <FormattedMessage
+          id='compose.hints.followers-reply'
+          defaultMessage="You're replying to a followers-only post. People not following {user} might see your reply without the context of what you’re replying to."
+          values={{ user: `@${replyFollowersHandle}` }}
+        />,
+      ),
+    );
+  }
+
+  if (isDifferentLanguage) {
+    messages.push(<LanguageHint guess={guess} />);
+  }
+
+  if (missingAlt && count === 1) {
+    messages.push(
+      defaultWrapper(
+        <FormattedMessage
+          id='compose.hints.missing-alt'
+          defaultMessage='Your attachment is missing alt text.'
+        />,
+      ),
+    );
+  } else if (missingAlt) {
+    messages.push(
+      defaultWrapper(
+        <FormattedMessage
+          id='compose.hints.missing-alt-many'
+          defaultMessage='One or more of your attachments are missing alt text.'
+        />,
+      ),
+    );
+  }
+
+  if (messages.length === 0) {
+    return null;
+  }
+
+  return <div>{messages}</div>;
+};
+
+const defaultWrapper = (children: React.ReactNode) => (
+  <Callout icon={WarningIcon}>{children}</Callout>
+);
+
+const LanguageHint: React.FC<{ guess: string }> = ({ guess }) => {
+  const languages = useLanguages();
+  const language = languages.find(([lang]) => lang === guess);
+
+  const { wasDismissed, dismiss } = useDismissible('compose_language_hint');
+
+  const dispatch = useAppDispatch();
+  const handleChange = useCallback(() => {
+    dispatch(changeComposeLanguage(guess));
+  }, [dispatch, guess]);
+
+  if (!language || wasDismissed) {
+    return null;
+  }
+
+  return (
+    <Callout
+      icon={WarningIcon}
+      actionClick={handleChange}
+      actionText={
+        <FormattedMessage
+          id='compose.hints.language.change'
+          defaultMessage='Change'
+          description='Label on button to accept language change prompt'
+        />
+      }
+      secondaryActionClick={dismiss}
+      secondaryActionText={
+        <FormattedMessage
+          id='compose.hints.language.dismiss'
+          defaultMessage='Dismiss'
+          description='Label on button to dismiss language change prompt'
+        />
+      }
+    >
+      <FormattedMessage
+        id='compose.hints.language'
+        defaultMessage='Change this post’s language to {language}?'
+        values={{
+          language: language[1],
+        }}
+      />
+    </Callout>
+  );
+};
diff --git a/app/javascript/mastodon/features/compose/redesign/hooks.ts b/app/javascript/mastodon/features/compose/redesign/hooks.ts
new file mode 100644
index 00000000000..d3c1ce14f06
--- /dev/null
+++ b/app/javascript/mastodon/features/compose/redesign/hooks.ts
@@ -0,0 +1,41 @@
+import { useEffect, useState } from 'react';
+
+import type { InitialStateLanguage } from '@/mastodon/initial_state';
+import { languages } from '@/mastodon/initial_state';
+import { useAppSelector } from '@/mastodon/store';
+
+const emptyArray: InitialStateLanguage[] = [];
+
+export function useLanguages() {
+  return languages ?? emptyArray;
+}
+
+export function useLanguageGuess() {
+  const text = useAppSelector((state) => state.compose.get('text') as string);
+  const [guess, setGuess] = useState('');
+
+  useEffect(() => {
+    void import('../util/language_detection').then(({ debouncedGuess }) => {
+      if (text.length > 20) {
+        debouncedGuess(text, setGuess);
+      } else {
+        debouncedGuess.cancel();
+      }
+    });
+  }, [text]);
+
+  // Keeping track of the previous render's text length here
+  // to be able to reset the guess when the text length drops
+  // below the threshold needed to make a guess
+  const isLongText = text.length > 20;
+  const [wasLongText, setWasLongText] = useState(() => isLongText);
+  if (wasLongText !== isLongText) {
+    setWasLongText(isLongText);
+
+    if (wasLongText) {
+      setGuess('');
+    }
+  }
+
+  return guess;
+}
diff --git a/app/javascript/mastodon/features/compose/redesign/index.tsx b/app/javascript/mastodon/features/compose/redesign/index.tsx
index 1aad10855aa..8095836a841 100644
--- a/app/javascript/mastodon/features/compose/redesign/index.tsx
+++ b/app/javascript/mastodon/features/compose/redesign/index.tsx
@@ -30,6 +30,7 @@ import { ComposeAttachments } from './attachments';
 import type { OnEmojiPick } from './emoji';
 import { ComposeFooter } from './footer';
 import { ComposeFormHeader } from './header';
+import { ComposeHints } from './hints';
 import { LanguageButton } from './language';
 import { ComposeReply } from './reply';
 import {
@@ -140,6 +141,8 @@ export const RedesignComposeForm: React.FC<RedesignComposeFormProps> = ({
         <ComposeAttachments />
       </div>
 
+      <ComposeHints />
+
       <ComposeFooter onEmojiPick={onEmojiPick} />
     </form>
   );
diff --git a/app/javascript/mastodon/features/compose/redesign/language.tsx b/app/javascript/mastodon/features/compose/redesign/language.tsx
index 374b49f4809..ab57a404572 100644
--- a/app/javascript/mastodon/features/compose/redesign/language.tsx
+++ b/app/javascript/mastodon/features/compose/redesign/language.tsx
@@ -1,5 +1,5 @@
 import type React from 'react';
-import { useCallback, useEffect, useRef, useState } from 'react';
+import { useCallback, useRef, useState } from 'react';
 
 import { FormattedMessage } from 'react-intl';
 
@@ -12,6 +12,7 @@ import { useAppDispatch, useAppSelector } from '@/mastodon/store';
 
 import { LanguageDropdownMenu } from '../components/language_dropdown';
 
+import { useLanguageGuess } from './hooks';
 import classes from './styles.module.scss';
 
 export const LanguageButton: React.FC = () => {
@@ -96,33 +97,3 @@ export const LanguageDropdown: React.FC<{ onClose: () => void }> = ({
     />
   );
 };
-
-function useLanguageGuess() {
-  const text = useAppSelector((state) => state.compose.get('text') as string);
-  const [guess, setGuess] = useState('');
-
-  useEffect(() => {
-    void import('../util/language_detection').then(({ debouncedGuess }) => {
-      if (text.length > 20) {
-        debouncedGuess(text, setGuess);
-      } else {
-        debouncedGuess.cancel();
-      }
-    });
-  }, [text]);
-
-  // Keeping track of the previous render's text length here
-  // to be able to reset the guess when the text length drops
-  // below the threshold needed to make a guess
-  const isLongText = text.length > 20;
-  const [wasLongText, setWasLongText] = useState(() => isLongText);
-  if (wasLongText !== isLongText) {
-    setWasLongText(isLongText);
-
-    if (wasLongText) {
-      setGuess('');
-    }
-  }
-
-  return guess;
-}
diff --git a/app/javascript/mastodon/initial_state.ts b/app/javascript/mastodon/initial_state.ts
index 29bad1d6729..d452ad88614 100644
--- a/app/javascript/mastodon/initial_state.ts
+++ b/app/javascript/mastodon/initial_state.ts
@@ -1,7 +1,11 @@
 import type { ApiAnnualReportState } from './api/annual_report';
 import type { ApiAccountJSON } from './api_types/accounts';
 
-type InitialStateLanguage = [code: string, name: string, localName: string];
+export type InitialStateLanguage = [
+  code: string,
+  name: string,
+  localName: string,
+];
 
 interface InitialStateMeta {
   access_token: string;
diff --git a/app/javascript/mastodon/locales/en.json b/app/javascript/mastodon/locales/en.json
index e88f0c730d2..544c131701e 100644
--- a/app/javascript/mastodon/locales/en.json
+++ b/app/javascript/mastodon/locales/en.json
@@ -494,6 +494,12 @@
   "compose.discoverable": "Discoverable in public feeds & search results",
   "compose.error.blank_post": "Post can't be blank.",
   "compose.expand": "Show composer",
+  "compose.hints.followers-reply": "You're replying to a followers-only post. People not following {user} might see your reply without the context of what you’re replying to.",
+  "compose.hints.language": "Change this post’s language to {language}?",
+  "compose.hints.language.change": "Change",
+  "compose.hints.language.dismiss": "Dismiss",
+  "compose.hints.missing-alt": "Your attachment is missing alt text.",
+  "compose.hints.missing-alt-many": "One or more of your attachments are missing alt text.",
   "compose.language.change": "Change language",
   "compose.language.search": "Search languages...",
   "compose.message.notice": "Messages are not end-to-end encrypted",