diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 3ccbb5ea85..404ced126b 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -1193,14 +1193,14 @@ reportDependentObjects(const ObjectAddresses *targetObjects,
 					(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
 					 errmsg("cannot drop %s because other objects depend on it",
 							getObjectDescription(origObject, false)),
-					 errdetail("%s", clientdetail.data),
+					 errdetail_internal("%s", clientdetail.data),
 					 errdetail_log("%s", logdetail.data),
 					 errhint("Use DROP ... CASCADE to drop the dependent objects too.")));
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
 					 errmsg("cannot drop desired object(s) because other objects depend on them"),
-					 errdetail("%s", clientdetail.data),
+					 errdetail_internal("%s", clientdetail.data),
 					 errdetail_log("%s", logdetail.data),
 					 errhint("Use DROP ... CASCADE to drop the dependent objects too.")));
 	}
@@ -1212,7 +1212,7 @@ reportDependentObjects(const ObjectAddresses *targetObjects,
 							   "drop cascades to %d other objects",
 							   numReportedClient + numNotReportedClient,
 							   numReportedClient + numNotReportedClient),
-				 errdetail("%s", clientdetail.data),
+				 errdetail_internal("%s", clientdetail.data),
 				 errdetail_log("%s", logdetail.data)));
 	}
 	else if (numReportedClient == 1)
diff --git a/src/backend/commands/user.c b/src/backend/commands/user.c
index 65bb733958..4621bba00e 100644
--- a/src/backend/commands/user.c
+++ b/src/backend/commands/user.c
@@ -567,7 +567,7 @@ AlterRole(AlterRoleStmt *stmt)
 	Oid			roleid;
 
 	check_rolespec_name(stmt->role,
-						"Cannot alter reserved roles.");
+						_("Cannot alter reserved roles."));
 
 	/* Extract options from the statement node tree */
 	foreach(option, stmt->options)
@@ -922,7 +922,7 @@ AlterRoleSet(AlterRoleSetStmt *stmt)
 	if (stmt->role)
 	{
 		check_rolespec_name(stmt->role,
-							"Cannot alter reserved roles.");
+							_("Cannot alter reserved roles."));
 
 		roletuple = get_rolespec_tuple(stmt->role);
 		roleform = (Form_pg_authid) GETSTRUCT(roletuple);
diff --git a/src/backend/utils/adt/acl.c b/src/backend/utils/adt/acl.c
index 67f8b29434..a44428da7a 100644
--- a/src/backend/utils/adt/acl.c
+++ b/src/backend/utils/adt/acl.c
@@ -5226,7 +5226,7 @@ get_rolespec_name(const RoleSpec *role)
 
 /*
  * Given a RoleSpec, throw an error if the name is reserved, using detail_msg,
- * if provided.
+ * if provided (which must be already translated).
  *
  * If node is NULL, no error is thrown.  If detail_msg is NULL then no detail
  * message is provided.
@@ -5247,7 +5247,7 @@ check_rolespec_name(const RoleSpec *role, const char *detail_msg)
 					(errcode(ERRCODE_RESERVED_NAME),
 					 errmsg("role name \"%s\" is reserved",
 							role->rolename),
-					 errdetail("%s", detail_msg)));
+					 errdetail_internal("%s", detail_msg)));
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_RESERVED_NAME),
diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index 5fd54b64b5..0364765dc0 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -615,13 +615,13 @@ json_ereport_error(JsonParseErrorType error, JsonLexContext *lex)
 		ereport(ERROR,
 				(errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
 				 errmsg("unsupported Unicode escape sequence"),
-				 errdetail("%s", json_errdetail(error, lex)),
+				 errdetail_internal("%s", json_errdetail(error, lex)),
 				 report_json_context(lex)));
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 				 errmsg("invalid input syntax for type %s", "json"),
-				 errdetail("%s", json_errdetail(error, lex)),
+				 errdetail_internal("%s", json_errdetail(error, lex)),
 				 report_json_context(lex)));
 }
 
diff --git a/src/common/jsonapi.c b/src/common/jsonapi.c
index d376ab152d..ade13aed3a 100644
--- a/src/common/jsonapi.c
+++ b/src/common/jsonapi.c
@@ -1052,7 +1052,7 @@ report_parse_error(JsonParseContext ctx, JsonLexContext *lex)
 }
 
 /*
- * Construct a detail message for a JSON error.
+ * Construct an (already translated) detail message for a JSON error.
  */
 char *
 json_errdetail(JsonParseErrorType error, JsonLexContext *lex)