diff --git a/Lib/fontTools/feaLib/builder.py b/Lib/fontTools/feaLib/builder.py
index da8ac539c..3fea2a6e9 100644
--- a/Lib/fontTools/feaLib/builder.py
+++ b/Lib/fontTools/feaLib/builder.py
@@ -193,6 +193,10 @@ class Builder(object):
             raise FeatureLibError(
                 "Within a named lookup block, it is not allowed "
                 "to change the language", location)
+        if self.cur_feature_name_ in ('aalt', 'size'):
+            raise FeatureLibError(
+                "Language statements are not allowed "
+                "within \"feature %s\"" % self.cur_feature_name_, location)
         self.cur_lookup_ = None
         if include_default:
             langsys = set(self.get_default_language_systems_())
@@ -206,6 +210,10 @@ class Builder(object):
             raise FeatureLibError(
                 "Within a named lookup block, it is not allowed "
                 "to change the script", location)
+        if self.cur_feature_name_ in ('aalt', 'size'):
+            raise FeatureLibError(
+                "Script statements are not allowed "
+                "within \"feature %s\"" % self.cur_feature_name_, location)
         self.cur_lookup_ = None
         self.script_ = script
         self.lookup_flag_ = 0
diff --git a/Lib/fontTools/feaLib/builder_test.py b/Lib/fontTools/feaLib/builder_test.py
index 9b69d0375..2d7db9c08 100644
--- a/Lib/fontTools/feaLib/builder_test.py
+++ b/Lib/fontTools/feaLib/builder_test.py
@@ -149,6 +149,12 @@ class BuilderTest(unittest.TestCase):
         self.assertEqual(builder.language_systems,
                          {('DFLT', 'dflt'), ('cyrl', 'dflt')})
 
+    def test_script_in_aalt_feature(self):
+        self.assertRaisesRegex(
+            FeatureLibError,
+            "Script statements are not allowed within \"feature aalt\"",
+            self.build, "feature aalt { script latn; } aalt;")
+
     def test_script_in_lookup_block(self):
         self.assertRaisesRegex(
             FeatureLibError,
@@ -156,6 +162,12 @@ class BuilderTest(unittest.TestCase):
             "to change the script",
             self.build, "lookup Foo { script latn; } Foo;")
 
+    def test_script_in_size_feature(self):
+        self.assertRaisesRegex(
+            FeatureLibError,
+            "Script statements are not allowed within \"feature size\"",
+            self.build, "feature size { script latn; } size;")
+
     def test_language(self):
         builder = Builder(None, TTFont())
         builder.add_language_system(None, 'latn', 'FRA ')
@@ -169,6 +181,12 @@ class BuilderTest(unittest.TestCase):
         self.assertEqual(builder.language_systems,
                          {('latn', 'FRA '), ('cyrl', 'BGR ')})
 
+    def test_language_in_aalt_feature(self):
+        self.assertRaisesRegex(
+            FeatureLibError,
+            "Language statements are not allowed within \"feature aalt\"",
+            self.build, "feature aalt { language FRA; } aalt;")
+
     def test_language_in_lookup_block(self):
         self.assertRaisesRegex(
             FeatureLibError,
@@ -176,6 +194,12 @@ class BuilderTest(unittest.TestCase):
             "to change the language",
             self.build, "lookup Foo { language RUS; } Foo;")
 
+    def test_language_in_size_feature(self):
+        self.assertRaisesRegex(
+            FeatureLibError,
+            "Language statements are not allowed within \"feature size\"",
+            self.build, "feature size { language FRA; } size;")
+
     def test_lookup_already_defined(self):
         self.assertRaisesRegex(
             FeatureLibError,