diff --git a/FAQ.md b/FAQ.md
index af5291748f..66bcc551e6 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -3055,6 +3055,9 @@ Example conditions:
 
 Note that *message("name")* returns an array. COALESCE returns the first value of an array, so it can be compared with a string value.
 
+Note that detecting the message text language needs to be enabled on the behavior settings tab page,
+and that changing this option doesn't affect the language detection of already received messages.
+
 <br>
 
 **Actions**
diff --git a/index.html b/index.html
index 1852f9ec4a..2fb735bbce 100644
--- a/index.html
+++ b/index.html
@@ -1677,6 +1677,7 @@ X-Google-Original-From: Somebody &lt;somebody+extra@example.org&gt;</code></pre>
 <p><code>AI("Is the message below a scam? Answer in English with just yes or no.") contains "yes"</code></p>
 <p><code>COALESCE(message("language")) == "en"</code></p>
 <p>Note that <em>message(“name”)</em> returns an array. COALESCE returns the first value of an array, so it can be compared with a string value.</p>
+<p>Note that detecting the message text language needs to be enabled on the behavior settings tab page, and that changing this option doesn’t affect the language detection of already received messages.</p>
 <p><br></p>
 <p><strong>Actions</strong></p>
 <p>You can select one of these actions to apply to matching messages:</p>