diff --git a/spec/README.md b/spec/README.md
index 465000ffe6..2cd29c9634 100644
--- a/spec/README.md
+++ b/spec/README.md
@@ -84,7 +84,7 @@ A reference to a _term_ looks like this.
 Updates to this specification will not change
 the syntactical meaning, the runtime output, or other behaviour
 of valid messages written for earlier versions of this specification
-that only use functions and expression attributes defined in this specification.
+that only use functions defined in this specification.
 Updates to this specification will not remove any syntax provided in this version.
 Future versions MAY add additional structure or meaning to existing syntax.
 
diff --git a/spec/data-model/README.md b/spec/data-model/README.md
index 6be5085f11..03ff05c857 100644
--- a/spec/data-model/README.md
+++ b/spec/data-model/README.md
@@ -136,33 +136,24 @@ interface LiteralExpression {
   type: "expression";
   arg: Literal;
   annotation?: FunctionAnnotation | UnsupportedAnnotation;
-  attributes?: Attribute[];
 }
 
 interface VariableExpression {
   type: "expression";
   arg: VariableRef;
   annotation?: FunctionAnnotation | UnsupportedAnnotation;
-  attributes?: Attribute[];
 }
 
 interface FunctionExpression {
   type: "expression";
   arg?: never;
   annotation: FunctionAnnotation;
-  attributes?: Attribute[];
 }
 
 interface UnsupportedExpression {
   type: "expression";
   arg?: never;
   annotation: UnsupportedAnnotation;
-  attributes?: Attribute[];
-}
-
-interface Attribute {
-  name: string;
-  value?: Literal | VariableRef;
 }
 ```
 
@@ -251,7 +242,6 @@ interface MarkupOpen {
   kind: "open";
   name: string;
   options?: Option[];
-  attributes?: Attribute[];
 }
 
 interface MarkupStandalone {
@@ -259,14 +249,12 @@ interface MarkupStandalone {
   kind: "standalone";
   name: string;
   options?: Option[];
-  attributes?: Attribute[];
 }
 
 interface MarkupClose {
   type: "markup";
   kind: "close";
   name: string;
-  attributes?: Attribute[];
 }
 ```
 
diff --git a/spec/data-model/message.dtd b/spec/data-model/message.dtd
index c6cb86c324..35a3fc6290 100644
--- a/spec/data-model/message.dtd
+++ b/spec/data-model/message.dtd
@@ -24,8 +24,8 @@
 <!ELEMENT pattern (#PCDATA | expression | markup)*>
 
 <!ELEMENT expression (
-  ((literal | variable), (functionAnnotation | unsupportedAnnotation)?, attribute*) |
-  ((functionAnnotation | unsupportedAnnotation), attribute*)
+  ((literal | variable), (functionAnnotation | unsupportedAnnotation)?) |
+  functionAnnotation | unsupportedAnnotation
 )>
 
 <!ELEMENT literal (#PCDATA)>
@@ -43,11 +43,8 @@
 <!ELEMENT unsupportedAnnotation (#PCDATA)>
 <!ATTLIST unsupportedAnnotation sigil CDATA #REQUIRED>
 
-<!ELEMENT attribute (literal | variable)?>
-<!ATTLIST attribute name NMTOKEN #REQUIRED>
-
 <!-- A <markup kind="close"> MUST NOT contain any <option> elements -->
-<!ELEMENT markup (option*, attribute*)>
+<!ELEMENT markup (option)*>
 <!ATTLIST markup
   kind (open | standalone | close) #REQUIRED
   name NMTOKEN #REQUIRED
diff --git a/spec/data-model/message.json b/spec/data-model/message.json
index 1ed01ceb2e..d130bb24c5 100644
--- a/spec/data-model/message.json
+++ b/spec/data-model/message.json
@@ -38,22 +38,6 @@
         "required": ["name", "value"]
       }
     },
-    "attributes": {
-      "type": "array",
-      "items": {
-        "type": "object",
-        "properties": {
-          "name": { "type": "string" },
-          "value": {
-            "oneOf": [
-              { "$ref": "#/$defs/literal" },
-              { "$ref": "#/$defs/variable" }
-            ]
-          }
-        },
-        "required": ["name"]
-      }
-    },
 
     "function-annotation": {
       "type": "object",
@@ -87,8 +71,7 @@
       "properties": {
         "type": { "const": "expression" },
         "arg": { "$ref": "#/$defs/literal" },
-        "annotation": { "$ref": "#/$defs/annotation" },
-        "attributes": { "$ref": "#/$defs/attributes" }
+        "annotation": { "$ref": "#/$defs/annotation" }
       },
       "required": ["type", "arg"]
     },
@@ -97,8 +80,7 @@
       "properties": {
         "type": { "const": "expression" },
         "arg": { "$ref": "#/$defs/variable" },
-        "annotation": { "$ref": "#/$defs/annotation" },
-        "attributes": { "$ref": "#/$defs/attributes" }
+        "annotation": { "$ref": "#/$defs/annotation" }
       },
       "required": ["type", "arg"]
     },
@@ -106,8 +88,7 @@
       "type": "object",
       "properties": {
         "type": { "const": "expression" },
-        "annotation": { "$ref": "#/$defs/function-annotation" },
-        "attributes": { "$ref": "#/$defs/attributes" }
+        "annotation": { "$ref": "#/$defs/function-annotation" }
       },
       "required": ["type", "annotation"]
     },
@@ -115,8 +96,7 @@
       "type": "object",
       "properties": {
         "type": { "const": "expression" },
-        "annotation": { "$ref": "#/$defs/unsupported-annotation" },
-        "attributes": { "$ref": "#/$defs/attributes" }
+        "annotation": { "$ref": "#/$defs/unsupported-annotation" }
       },
       "required": ["type", "annotation"]
     },
@@ -135,8 +115,7 @@
         "type": { "const": "markup" },
         "kind": { "const": "open" },
         "name": { "type": "string" },
-        "options": { "$ref": "#/$defs/options" },
-        "attributes": { "$ref": "#/$defs/attributes" }
+        "options": { "$ref": "#/$defs/options" }
       },
       "required": ["type", "kind", "name"]
     },
@@ -146,8 +125,7 @@
         "type": { "const": "markup" },
         "kind": { "const": "standalone" },
         "name": { "type": "string" },
-        "options": { "$ref": "#/$defs/options" },
-        "attributes": { "$ref": "#/$defs/attributes" }
+        "options": { "$ref": "#/$defs/options" }
       },
       "required": ["type", "kind", "name"]
     },
@@ -156,8 +134,7 @@
       "properties": {
         "type": { "const": "markup" },
         "kind": { "const": "close" },
-        "name": { "type": "string" },
-        "attributes": { "$ref": "#/$defs/attributes" }
+        "name": { "type": "string" }
       },
       "required": ["type", "kind", "name"]
     },