diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 66742c94f057e..664fe44caf95e 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -38003,7 +38003,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         const exprType = checkExpression(expression, checkMode);
         if (isConstTypeReference(type)) {
             if (!isValidConstAssertionArgument(expression)) {
-                error(expression, Diagnostics.A_const_assertions_can_only_be_applied_to_references_to_enum_members_or_string_number_boolean_array_or_object_literals);
+                error(expression, Diagnostics.A_const_assertion_can_only_be_applied_to_references_to_enum_members_or_string_number_boolean_array_or_object_literals);
             }
             return getRegularTypeOfLiteralType(exprType);
         }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 22ac200a0dcee..af0881786459a 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1155,7 +1155,7 @@
         "category": "Error",
         "code": 1354
     },
-    "A 'const' assertions can only be applied to references to enum members, or string, number, boolean, array, or object literals.": {
+    "A 'const' assertion can only be applied to references to enum members, or string, number, boolean, array, or object literals.": {
         "category": "Error",
         "code": 1355
     },
diff --git a/tests/baselines/reference/constAssertions.errors.txt b/tests/baselines/reference/constAssertions.errors.txt
index 99db0753d705f..d86f75c5906eb 100644
--- a/tests/baselines/reference/constAssertions.errors.txt
+++ b/tests/baselines/reference/constAssertions.errors.txt
@@ -1,7 +1,7 @@
 constAssertions.ts(44,32): error TS2540: Cannot assign to 'x' because it is a read-only property.
-constAssertions.ts(61,10): error TS1355: A 'const' assertions can only be applied to references to enum members, or string, number, boolean, array, or object literals.
-constAssertions.ts(62,10): error TS1355: A 'const' assertions can only be applied to references to enum members, or string, number, boolean, array, or object literals.
-constAssertions.ts(63,10): error TS1355: A 'const' assertions can only be applied to references to enum members, or string, number, boolean, array, or object literals.
+constAssertions.ts(61,10): error TS1355: A 'const' assertion can only be applied to references to enum members, or string, number, boolean, array, or object literals.
+constAssertions.ts(62,10): error TS1355: A 'const' assertion can only be applied to references to enum members, or string, number, boolean, array, or object literals.
+constAssertions.ts(63,10): error TS1355: A 'const' assertion can only be applied to references to enum members, or string, number, boolean, array, or object literals.
 constAssertions.ts(118,3): error TS2322: Type '3' is not assignable to type '2'.
 
 
@@ -70,13 +70,13 @@ constAssertions.ts(118,3): error TS2322: Type '3' is not assignable to type '2'.
     
     let e1 = v1 as const;  // Error
              ~~
-!!! error TS1355: A 'const' assertions can only be applied to references to enum members, or string, number, boolean, array, or object literals.
+!!! error TS1355: A 'const' assertion can only be applied to references to enum members, or string, number, boolean, array, or object literals.
     let e2 = (true ? 1 : 0) as const;  // Error
              ~~~~~~~~~~~~~~
-!!! error TS1355: A 'const' assertions can only be applied to references to enum members, or string, number, boolean, array, or object literals.
+!!! error TS1355: A 'const' assertion can only be applied to references to enum members, or string, number, boolean, array, or object literals.
     let e3 = id(1) as const;  // Error
              ~~~~~
-!!! error TS1355: A 'const' assertions can only be applied to references to enum members, or string, number, boolean, array, or object literals.
+!!! error TS1355: A 'const' assertion can only be applied to references to enum members, or string, number, boolean, array, or object literals.
     
     let t1 = 'foo' as const;
     let t2 = 'bar' as const;
diff --git a/tests/baselines/reference/constantEnumAssert.errors.txt b/tests/baselines/reference/constantEnumAssert.errors.txt
index 48c3188974673..de8943cd7f2b1 100644
--- a/tests/baselines/reference/constantEnumAssert.errors.txt
+++ b/tests/baselines/reference/constantEnumAssert.errors.txt
@@ -1,4 +1,4 @@
-constantEnumAssert.ts(49,20): error TS1355: A 'const' assertions can only be applied to references to enum members, or string, number, boolean, array, or object literals.
+constantEnumAssert.ts(49,20): error TS1355: A 'const' assertion can only be applied to references to enum members, or string, number, boolean, array, or object literals.
 
 
 ==== constantEnumAssert.ts (1 errors) ====
@@ -52,5 +52,5 @@ constantEnumAssert.ts(49,20): error TS1355: A 'const' assertions can only be app
     
     const foo12 = { a: E5.a as const }
                        ~~~~
-!!! error TS1355: A 'const' assertions can only be applied to references to enum members, or string, number, boolean, array, or object literals.
+!!! error TS1355: A 'const' assertion can only be applied to references to enum members, or string, number, boolean, array, or object literals.
     
\ No newline at end of file