diff --git a/common/web/types/src/ldml-keyboard/pattern-parser.ts b/common/web/types/src/ldml-keyboard/pattern-parser.ts
index 3e56096ec6..297de9d0b2 100644
--- a/common/web/types/src/ldml-keyboard/pattern-parser.ts
+++ b/common/web/types/src/ldml-keyboard/pattern-parser.ts
@@ -81,7 +81,12 @@ export class MarkerParser {
   /**
    * Pattern for matching a marker reference, OR the special marker \m{.}
    */
-  public static readonly REFERENCE = /\\m{([0-9A-Za-z_]{1,32}|\.)}/g;
+  public static readonly REFERENCE = /(?<!\\)(?:\\\\)*\\m{([0-9A-Za-z_]{1,32}|\.)}/g;
+
+  /**
+   * Pattern for matching a broken marker reference (assuming REFERENCE was not matched)
+   */
+  public static readonly BROKEN_REFERENCE = /(?<!\\)(?:\\\\)*\\m{([^}\\{}]*)/g;
 
   /**
    * parse a string into marker references
@@ -95,6 +100,21 @@ export class MarkerParser {
     return matchArray(str, MarkerParser.REFERENCE);
   }
 
+  /**
+   * parse a string for broken marker references
+   * @param str input string such as "\m{a} … \m{.}"
+   * @returns `[]` or an array of all broken markers referenced
+   */
+  public static allBrokenReferences(str: string): string[] {
+    if (!str) {
+      return [];
+    }
+    // exclude valid markers
+    str = str.replaceAll(this.REFERENCE, '');
+    return matchArray(str, MarkerParser.BROKEN_REFERENCE);
+  }
+
+
   private static markerCodeToString(n: number, forMatch?: boolean): string {
     if (!forMatch) {
       return String.fromCharCode(n);
diff --git a/common/web/types/test/ldml-keyboard/test-pattern-parser.ts b/common/web/types/test/ldml-keyboard/test-pattern-parser.ts
index 01d5a183c2..bf45933d15 100644
--- a/common/web/types/test/ldml-keyboard/test-pattern-parser.ts
+++ b/common/web/types/test/ldml-keyboard/test-pattern-parser.ts
@@ -33,7 +33,7 @@ describe('Test of Pattern Parsers', () => {
     // indirectly tests REFERENCE
     it('should match reference strings', () => {
       const cases: string[][] = [
-        ['\\m{acute}', 'acute'],
+        ['\\m{acute} but not \\\\m{chronic}', 'acute'], // second marker is escaped
         ['\\m{acute}≈\\m{acute}', 'acute acute'], // not deduped
         ['\\m{grave}≠\\m{acute}', 'grave acute'],
         [MarkerParser.ANY_MARKER, MarkerParser.ANY_MARKER_ID],
@@ -55,6 +55,19 @@ describe('Test of Pattern Parsers', () => {
         assert.deepEqual(MarkerParser.allReferences(str), [], `expected no markers: ${str}`);
       }
     });
+    it('should match broken reference strings', () => {
+      const cases: string[][] = [
+        // hyphenated marker id - illegal
+        ['\\m{chronic} \\m{a-cute} \\\\m{a-choo}', 'a-cute'], // \\m{a-choo} is literal
+        // marker through end of line
+        ['\\m{chronic} \\m{oopsIforGot to terminate it', 'oopsIforGot to terminate it'],
+        // marker terminated by other valid marker
+        ['\\m{chronic} \\m{what \\m{does} \\m{this button do?', 'what  ', 'this button do?'],
+      ];
+      for (const [str, ...reflist] of cases) {
+        assert.sameDeepMembers(MarkerParser.allBrokenReferences(str), reflist, `for ${str}`);
+      }
+    });
     it('should be able to emit sentinel values', () => {
       assert.equal(MarkerParser.markerOutput(295), '\uFFFF\u0008\u0127', 'Wrong sentinel value emitted');
       assert.equal(MarkerParser.markerOutput(MarkerParser.ANY_MARKER_INDEX), '\uFFFF\u0008\uD7FF', 'Wrong sentinel value emitted for ANY_MARKER_INDEX');