diff --git a/src/serializer.ts b/src/serializer.ts
index 58d7a7e..fcfc383 100644
--- a/src/serializer.ts
+++ b/src/serializer.ts
@@ -3,6 +3,18 @@ import { JsonataASTNode, ObjectUnaryNode, ArrayUnaryNode } from "./types";
 // TODO: Should eventually replace this with types from the `jsonata` package once they're complete.
 type AST = JsonataASTNode;
 
+export function escapeString(name:string){
+  if (
+    /\s/.test(name) 
+    || ["null", "false", "true"].includes(name) 
+    || /^\d/.test(name)
+    || !(/^[a-zA-Z()]+$/.test(name))
+  ) {
+    return "`" + name + "`";
+  }
+  return name;
+}
+
 export default function serializer(node: AST): string {
   if(!node) return undefined;
   if (node.type === "binary") {
@@ -61,10 +73,7 @@ export default function serializer(node: AST): string {
       bind = "@" + index + focus
     }
     let name = node.value;
-    if (/\s/.test(name) || ["null", "false", "true"].includes(name)) {
-      // Escaped for whitespace
-      name = "`" + name + "`";
-    }
+    name = escapeString(name);
     return name + bind + stages;
   } else if (node.type === "filter") {
     return "[" + serializer(node.expr) + "]";
diff --git a/test/features/Serializer.feature b/test/features/Serializer.feature
index 4146755..6c06f0b 100644
--- a/test/features/Serializer.feature
+++ b/test/features/Serializer.feature
@@ -36,5 +36,30 @@ Feature: AST Serializer
             | loans@$foo#$bar |
             | loans@$foo      |
             | loans#$bar      |
+            | foo-bar         |
+            | foo+bar         |
+            | foo/bar         |
+            | foo*bar         |
+            | `😊`          |
+            | "foo-bar"       |
+            | "foo+bar"       |
+            | "foo/bar"       |
+            | "foo*bar"       |
+            | "foo-bar"       |
+            | "foo+bar"       |
+            | "foo/bar"       |
+            | "foo*bar"       |
+            | "\""            |
+            | foo_bar         |
+            | `foo_bar`       |
+            | foo1bar         |
+            | foobar1         |
+            | foobar_1        |
+            | `1foobar`       |
+            | `foo-bar`       |
+            | `foo+bar`       |
+            | `foo/bar`       |
+            | `foo*bar`       |
+            | `foobar-1`      |