diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 5f61561eea..30d4507eb3 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1249,6 +1249,21 @@ testdb=>
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><literal>\dL[S+] [ <link linkend="APP-PSQL-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists all procedural languages. If <replaceable
+        class="parameter">pattern</replaceable>
+        is specified, only languages whose names match the pattern are listed.
+        By default, only user-created languages
+        are shown; supply the <literal>S</literal> modifier to include system
+        objects. If <literal>+</literal> is appended to the command name, each
+        language is listed with its call handler, validator, access privileges,
+        and whether it is a system object.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dn[S+] [ <link linkend="APP-PSQL-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 962c13c136..301dc11bcc 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -416,6 +416,9 @@ exec_command(const char *cmd,
 			case 'l':
 				success = do_lo_list();
 				break;
+			case 'L':
+				success = listLanguages(pattern, show_verbose, show_system);
+				break;
 			case 'n':
 				success = listSchemas(pattern, show_verbose, show_system);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 205190f729..e9436f862a 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2566,6 +2566,74 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
 }
 
 
+/*
+ * \dL
+ *
+ * Describes languages.
+ */
+bool
+listLanguages(const char *pattern, bool verbose, bool showSystem)
+{
+	PQExpBufferData buf;
+	PGresult *res;
+	printQueryOpt myopt = pset.popt;
+
+	initPQExpBuffer(&buf);
+
+	printfPQExpBuffer(&buf,
+					  "SELECT l.lanname AS \"%s\",\n",
+					  gettext_noop("Name"));
+	if (pset.sversion >= 80300)
+			appendPQExpBuffer(&buf,
+							  "       pg_catalog.pg_get_userbyid(l.lanowner) as \"%s\",\n",
+							  gettext_noop("Owner"));
+
+	appendPQExpBuffer(&buf,
+					  "       l.lanpltrusted AS \"%s\"",
+					  gettext_noop("Trusted"));
+
+	if (verbose)
+	{
+			appendPQExpBuffer(&buf,
+							  ",\n       NOT l.lanispl AS \"%s\",\n"
+							  "       l.lanplcallfoid::regprocedure AS \"%s\",\n"
+							  "       l.lanvalidator::regprocedure AS \"%s\",\n       ",
+							  gettext_noop("Internal Language"),
+							  gettext_noop("Call Handler"),
+							  gettext_noop("Validator"));
+			if (pset.sversion >= 90000)
+				appendPQExpBuffer(&buf, "l.laninline::regprocedure AS \"%s\",\n       ",
+								  gettext_noop("Inline Handler"));
+			printACLColumn(&buf, "l.lanacl");
+	}
+
+	appendPQExpBuffer(&buf,
+					  "\nFROM pg_catalog.pg_language l\n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false, false,
+						  NULL, "l.lanname", NULL, NULL);
+
+	if (!showSystem && !pattern)
+		appendPQExpBuffer(&buf, "WHERE lanplcallfoid != 0\n");
+
+	appendPQExpBuffer(&buf, "ORDER BY 1;");
+
+	res = PSQLexec(buf.data, false);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of languages");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
+
 /*
  * \dD
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 2029ef848d..4e80bcf41f 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -84,5 +84,7 @@ extern bool listUserMappings(const char *pattern, bool verbose);
 /* \det */
 extern bool listForeignTables(const char *pattern, bool verbose);
 
+/* \dL */
+extern bool listLanguages(const char *pattern, bool verbose, bool showSystem);
 
 #endif   /* DESCRIBE_H */
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 96c85a25d6..bd5c4b767b 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -211,6 +211,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\dg[+]  [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\di[S+] [PATTERN]      list indexes\n"));
 	fprintf(output, _("  \\dl                    list large objects, same as \\lo_list\n"));
+	fprintf(output, _("  \\dL[S+] [PATTERN]      list procedural languages\n"));
 	fprintf(output, _("  \\dn[+]  [PATTERN]      list schemas\n"));
 	fprintf(output, _("  \\do[S]  [PATTERN]      list operators\n"));
 	fprintf(output, _("  \\dp     [PATTERN]      list table, view, and sequence access privileges\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 8c15838555..84c68a7bff 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -713,7 +713,7 @@ psql_completion(char *text, int start, int end)
 	static const char *const backslash_commands[] = {
 		"\\a", "\\connect", "\\conninfo", "\\C", "\\cd", "\\copy", "\\copyright",
 		"\\d", "\\da", "\\db", "\\dc", "\\dC", "\\dd", "\\dD", "\\des", "\\det", "\\deu", "\\dew", "\\df",
-		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl",
+		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dn", "\\do", "\\dp", "\\drds", "\\ds", "\\dS", "\\dt", "\\dT", "\\dv", "\\du",
 		"\\e", "\\echo", "\\ef", "\\encoding",
 		"\\f", "\\g", "\\h", "\\help", "\\H", "\\i", "\\l",
@@ -2680,6 +2680,8 @@ psql_completion(char *text, int start, int end)
 
 	else if (strncmp(prev_wd, "\\di", strlen("\\di")) == 0)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_indexes, NULL);
+	else if (strncmp(prev_wd, "\\dL", strlen("\\dL")) == 0)
+		COMPLETE_WITH_QUERY(Query_for_list_of_languages);
 	else if (strncmp(prev_wd, "\\dn", strlen("\\dn")) == 0)
 		COMPLETE_WITH_QUERY(Query_for_list_of_schemas);
 	else if (strncmp(prev_wd, "\\dp", strlen("\\dp")) == 0