diff --git a/src/Utils/Utils.php b/src/Utils/Utils.php
index 853fbf1..c9c3452 100644
--- a/src/Utils/Utils.php
+++ b/src/Utils/Utils.php
@@ -512,6 +512,9 @@ class Utils
      * Given an invalid input string and a list of valid options, returns a filtered
      * list of valid options sorted based on their similarity with the input.
      *
+     * Includes a custom alteration from Damerau-Levenshtein to treat case changes
+     * as a single edit which helps identify mis-cased values with an edit distance
+     * of 1
      * @param string $input
      * @param array $options
      * @return string[]
@@ -521,7 +524,11 @@ class Utils
         $optionsByDistance = [];
         $inputThreshold = mb_strlen($input) / 2;
         foreach ($options as $option) {
-            $distance = levenshtein($input, $option);
+            $distance = $input === $option
+                ? 0
+                : (strtolower($input) === strtolower($option)
+                    ? 1
+                    : levenshtein($input, $option));
             $threshold = max($inputThreshold, mb_strlen($option) / 2, 1);
             if ($distance <= $threshold) {
                 $optionsByDistance[$option] = $distance;
diff --git a/src/Utils/Value.php b/src/Utils/Value.php
index 6d45c49..5606091 100644
--- a/src/Utils/Value.php
+++ b/src/Utils/Value.php
@@ -2,6 +2,7 @@
 namespace GraphQL\Utils;
 
 use GraphQL\Error\Error;
+use GraphQL\Language\AST\Node;
 use GraphQL\Type\Definition\EnumType;
 use GraphQL\Type\Definition\InputObjectType;
 use GraphQL\Type\Definition\InputType;
@@ -26,7 +27,7 @@ class Value
             if ($value === null) {
                 return self::ofErrors([
                     self::coercionError(
-                        "Expected non-nullable type $type",
+                        "Expected non-nullable type $type not to be null",
                         $blameNode,
                         $path
                     ),
@@ -55,11 +56,23 @@ class Value
                 return self::ofValue($parseResult);
             } catch (\Exception $error) {
                 return self::ofErrors([
-                    self::coercionError("Expected type {$type->name}", $blameNode, $path, $error),
+                    self::coercionError(
+                        "Expected type {$type->name}",
+                        $blameNode,
+                        $path,
+                        $error->getMessage(),
+                        $error
+                    ),
                 ]);
             } catch (\Throwable $error) {
                 return self::ofErrors([
-                    self::coercionError("Expected type {$type->name}", $blameNode, $path, $error),
+                    self::coercionError(
+                        "Expected type {$type->name}",
+                        $blameNode,
+                        $path,
+                        $error->getMessage(),
+                        $error
+                    ),
                 ]);
             }
         }
@@ -72,8 +85,21 @@ class Value
                 }
             }
 
+            $suggestions = Utils::suggestionList(
+                Utils::printSafe($value),
+                array_map(function($enumValue) { return $enumValue->name; }, $type->getValues())
+            );
+            $didYouMean = $suggestions
+                ? "did you mean " . Utils::orList($suggestions) . "?"
+                : null;
+
             return self::ofErrors([
-                self::coercionError("Expected type {$type->name}", $blameNode, $path),
+                self::coercionError(
+                    "Expected type {$type->name}",
+                    $blameNode,
+                    $path,
+                    $didYouMean
+                ),
             ]);
         }
 
@@ -105,7 +131,11 @@ class Value
         if ($type instanceof InputObjectType) {
             if (!is_object($value) && !is_array($value) && !$value instanceof \Traversable) {
                 return self::ofErrors([
-                    self::coercionError("Expected object type {$type->name}", $blameNode, $path),
+                    self::coercionError(
+                        "Expected type {$type->name} to be an object",
+                        $blameNode,
+                        $path
+                    ),
                 ]);
             }
 
@@ -146,12 +176,20 @@ class Value
             // Ensure every provided field is defined.
             foreach ($value as $fieldName => $field) {
                 if (!array_key_exists($fieldName, $fields)) {
+                    $suggestions = Utils::suggestionList(
+                        $fieldName,
+                        array_keys($fields)
+                    );
+                    $didYouMean = $suggestions
+                        ? "did you mean " . Utils::orList($suggestions) . "?"
+                        : null;
                     $errors = self::add(
                         $errors,
                         self::coercionError(
                             "Field \"{$fieldName}\" is not defined by type {$type->name}",
                             $blameNode,
-                            $path
+                            $path,
+                            $didYouMean
                         )
                     );
                 }
@@ -183,18 +221,17 @@ class Value
      * @param string $message
      * @param Node $blameNode
      * @param array|null $path
+     * @param string $subMessage
      * @param \Exception|\Throwable|null $originalError
      * @return Error
      */
-    private static function coercionError($message, $blameNode, array $path = null, $originalError = null) {
+    private static function coercionError($message, $blameNode, array $path = null, $subMessage = null, $originalError = null) {
         $pathStr = self::printPath($path);
         // Return a GraphQLError instance
         return new Error(
             $message .
             ($pathStr ? ' at ' . $pathStr : '') .
-            ($originalError && $originalError->getMessage()
-                ? '; ' . $originalError->getMessage()
-                : '.'),
+            ($subMessage ? '; ' . $subMessage : '.'),
             $blameNode,
             null,
             null,
diff --git a/src/Validator/Rules/ValuesOfCorrectType.php b/src/Validator/Rules/ValuesOfCorrectType.php
index a70de1f..c77c93b 100644
--- a/src/Validator/Rules/ValuesOfCorrectType.php
+++ b/src/Validator/Rules/ValuesOfCorrectType.php
@@ -45,9 +45,12 @@ class ValuesOfCorrectType extends AbstractValidationRule
             "{$fieldTypeName} was not provided.";
     }
 
-    static function unknownFieldMessage($typeName, $fieldName)
+    static function unknownFieldMessage($typeName, $fieldName, $message = null)
     {
-        return "Field \"{$fieldName}\" is not defined by type {$typeName}.";
+        return (
+            "Field \"{$fieldName}\" is not defined by type {$typeName}" .
+            ($message ? "; {$message}" : '.')
+        );
     }
 
     public function getVisitor(ValidationContext $context)
@@ -103,10 +106,18 @@ class ValuesOfCorrectType extends AbstractValidationRule
             NodeKind::OBJECT_FIELD => function(ObjectFieldNode $node) use ($context) {
                 $parentType = Type::getNamedType($context->getParentInputType());
                 $fieldType = $context->getInputType();
-                if (!$fieldType && $parentType) {
+                if (!$fieldType && $parentType instanceof InputObjectType) {
+                    $suggestions = Utils::suggestionList(
+                        $node->name->value,
+                        array_keys($parentType->getFields())
+                    );
+                    $didYouMean = $suggestions
+                        ? "Did you mean " . Utils::orList($suggestions) . "?"
+                        : null;
+
                     $context->reportError(
                         new Error(
-                            self::unknownFieldMessage($parentType->name, $node->name->value),
+                            self::unknownFieldMessage($parentType->name, $node->name->value, $didYouMean),
                             $node
                         )
                     );
@@ -148,15 +159,12 @@ class ValuesOfCorrectType extends AbstractValidationRule
         $type = Type::getNamedType($locationType);
 
         if (!$type instanceof ScalarType) {
-            $suggestions = $type instanceof EnumType
-                ? $this->enumTypeSuggestion($type, $node)
-                : null;
             $context->reportError(
                 new Error(
                     self::badValueMessage(
                         (string) $locationType,
                         Printer::doPrint($node),
-                        $suggestions
+                        $this->enumTypeSuggestion($type, $node)
                     ),
                     $node
                 )
@@ -214,13 +222,17 @@ class ValuesOfCorrectType extends AbstractValidationRule
         }
     }
 
-    private function enumTypeSuggestion(EnumType $type, ValueNode $node)
+    private function enumTypeSuggestion($type, ValueNode $node)
     {
-        $suggestions = Utils::suggestionList(
-            Printer::doPrint($node),
-            array_map(function (EnumValueDefinition $value) { return $value->name; }, $type->getValues())
-        );
+        if ($type instanceof EnumType) {
+            $suggestions = Utils::suggestionList(
+                Printer::doPrint($node),
+                array_map(function (EnumValueDefinition $value) {
+                    return $value->name;
+                }, $type->getValues())
+            );
 
-        return $suggestions ? 'Did you mean the enum value: ' . Utils::orList($suggestions) . '?' : '';
+            return $suggestions ? 'Did you mean the enum value ' . Utils::orList($suggestions) . '?' : null;
+        }
     }
 }
diff --git a/tests/Executor/VariablesTest.php b/tests/Executor/VariablesTest.php
index ccb16bb..89c931f 100644
--- a/tests/Executor/VariablesTest.php
+++ b/tests/Executor/VariablesTest.php
@@ -160,7 +160,7 @@ class VariablesTest extends \PHPUnit_Framework_TestCase
                     'message' =>
                         'Variable "$input" got invalid value ' .
                         '{"a":"foo","b":"bar","c":null}; ' .
-                        'Expected non-nullable type String! at value.c.',
+                        'Expected non-nullable type String! not to be null at value.c.',
                     'locations' => [['line' => 2, 'column' => 17]],
                     'category' => 'graphql'
                 ]
@@ -177,7 +177,7 @@ class VariablesTest extends \PHPUnit_Framework_TestCase
                 [
                     'message' =>
                         'Variable "$input" got invalid value "foo bar"; ' .
-                        'Expected object type TestInputObject.',
+                        'Expected type TestInputObject to be an object.',
                     'locations' => [ [ 'line' => 2, 'column' => 17 ] ],
                     'category' => 'graphql',
                 ]
@@ -411,7 +411,7 @@ class VariablesTest extends \PHPUnit_Framework_TestCase
                 [
                     'message' =>
                         'Variable "$value" got invalid value null; ' .
-                        'Expected non-nullable type String!.',
+                        'Expected non-nullable type String! not to be null.',
                     'locations' => [['line' => 2, 'column' => 31]],
                     'category' => 'graphql',
                 ]
@@ -613,7 +613,7 @@ class VariablesTest extends \PHPUnit_Framework_TestCase
                 [
                     'message' =>
                         'Variable "$input" got invalid value null; ' .
-                        'Expected non-nullable type [String]!.',
+                        'Expected non-nullable type [String]! not to be null.',
                     'locations' => [['line' => 2, 'column' => 17]],
                     'category' => 'graphql',
                 ]
@@ -701,7 +701,7 @@ class VariablesTest extends \PHPUnit_Framework_TestCase
                 [
                     'message' =>
                         'Variable "$input" got invalid value ["A",null,"B"]; ' .
-                        'Expected non-nullable type String! at value[1].',
+                        'Expected non-nullable type String! not to be null at value[1].',
                     'locations' => [ ['line' => 2, 'column' => 17] ],
                     'category' => 'graphql',
                 ]
@@ -727,7 +727,7 @@ class VariablesTest extends \PHPUnit_Framework_TestCase
                 [
                     'message' =>
                         'Variable "$input" got invalid value null; ' .
-                        'Expected non-nullable type [String!]!.',
+                        'Expected non-nullable type [String!]! not to be null.',
                     'locations' => [ ['line' => 2, 'column' => 17] ],
                     'category' => 'graphql',
                 ]
@@ -768,7 +768,7 @@ class VariablesTest extends \PHPUnit_Framework_TestCase
                 [
                     'message' =>
                         'Variable "$input" got invalid value ["A",null,"B"]; ' .
-                        'Expected non-nullable type String! at value[1].',
+                        'Expected non-nullable type String! not to be null at value[1].',
                     'locations' => [ ['line' => 2, 'column' => 17] ],
                     'category' => 'graphql',
                 ]
diff --git a/tests/Type/EnumTypeTest.php b/tests/Type/EnumTypeTest.php
index 9c6910d..79741d3 100644
--- a/tests/Type/EnumTypeTest.php
+++ b/tests/Type/EnumTypeTest.php
@@ -220,7 +220,7 @@ class EnumTypeTest extends \PHPUnit_Framework_TestCase
             '{ colorEnum(fromEnum: "GREEN") }',
             null,
             [
-                'message' => "Expected type Color, found \"GREEN\"; Did you mean the enum value: GREEN?",
+                'message' => "Expected type Color, found \"GREEN\"; Did you mean the enum value GREEN?",
                 'locations' => [new SourceLocation(1, 23)]
             ]
         );
@@ -235,7 +235,22 @@ class EnumTypeTest extends \PHPUnit_Framework_TestCase
             '{ colorEnum(fromEnum: GREENISH) }',
             null,
             [
-                'message' => "Expected type Color, found GREENISH; Did you mean the enum value: GREEN?",
+                'message' => "Expected type Color, found GREENISH; Did you mean the enum value GREEN?",
+                'locations' => [new SourceLocation(1, 23)]
+            ]
+        );
+    }
+
+    /**
+     * @it does not accept values with incorrect casing
+     */
+    public function testDoesNotAcceptValuesWithIncorrectCasing()
+    {
+        $this->expectFailure(
+            '{ colorEnum(fromEnum: green) }',
+            null,
+            [
+                'message' => "Expected type Color, found green; Did you mean the enum value GREEN?",
                 'locations' => [new SourceLocation(1, 23)]
             ]
         );
diff --git a/tests/Utils/CoerceValueTest.php b/tests/Utils/CoerceValueTest.php
index 999ca89..bb5823a 100644
--- a/tests/Utils/CoerceValueTest.php
+++ b/tests/Utils/CoerceValueTest.php
@@ -1,12 +1,38 @@
 <?php
 namespace GraphQL\Tests\Utils;
 
+use GraphQL\Error\Error;
 use GraphQL\Executor\Values;
+use GraphQL\Type\Definition\EnumType;
+use GraphQL\Type\Definition\InputObjectType;
 use GraphQL\Type\Definition\Type;
+use GraphQL\Utils\Utils;
 use GraphQL\Utils\Value;
 
 class CoerceValueTest extends \PHPUnit_Framework_TestCase
 {
+    private $testEnum;
+    private $testInputObject;
+
+    public function setUp()
+    {
+        $this->testEnum = new EnumType([
+            'name' => 'TestEnum',
+            'values' => [
+                'FOO' => 'InternalFoo',
+                'BAR' => 123456789,
+            ],
+        ]);
+
+        $this->testInputObject = new InputObjectType([
+            'name' => 'TestInputObject',
+            'fields' => [
+                'foo' => Type::nonNull(Type::int()),
+                'bar' => Type::int(),
+            ],
+        ]);
+    }
+
     // Describe: coerceValue
 
     /**
@@ -186,16 +212,125 @@ class CoerceValueTest extends \PHPUnit_Framework_TestCase
         );
     }
 
+    // DESCRIBE: for GraphQLEnum
+
+    /**
+     * @it returns no error for a known enum name
+     */
+    public function testReturnsNoErrorForAKnownEnumName()
+    {
+        $fooResult = Value::coerceValue('FOO', $this->testEnum);
+        $this->expectNoErrors($fooResult);
+        $this->assertEquals('InternalFoo', $fooResult['value']);
+
+        $barResult = Value::coerceValue('BAR', $this->testEnum);
+        $this->expectNoErrors($barResult);
+        $this->assertEquals(123456789, $barResult['value']);
+    }
+
+    /**
+     * @it results error for misspelled enum value
+     */
+    public function testReturnsErrorForMisspelledEnumValue()
+    {
+        $result = Value::coerceValue('foo', $this->testEnum);
+        $this->expectError($result, 'Expected type TestEnum; did you mean FOO?');
+    }
+
+    /**
+     * @it results error for incorrect value type
+     */
+    public function testReturnsErrorForIncorrectValueType()
+    {
+        $result1 = Value::coerceValue(123, $this->testEnum);
+        $this->expectError($result1, 'Expected type TestEnum.');
+
+        $result2 = Value::coerceValue(['field' => 'value'], $this->testEnum);
+        $this->expectError($result2, 'Expected type TestEnum.');
+    }
+
+    // DESCRIBE: for GraphQLInputObject
+
+    /**
+     * @it returns no error for a valid input
+     */
+    public function testReturnsNoErrorForValidInput()
+    {
+        $result = Value::coerceValue(['foo' => 123], $this->testInputObject);
+        $this->expectNoErrors($result);
+        $this->assertEquals(['foo' => 123], $result['value']);
+    }
+
+    /**
+     * @it returns no error for a non-object type
+     */
+    public function testReturnsErrorForNonObjectType()
+    {
+        $result = Value::coerceValue(123, $this->testInputObject);
+        $this->expectError($result, 'Expected type TestInputObject to be an object.');
+    }
+
+    /**
+     * @it returns no error for an invalid field
+     */
+    public function testReturnErrorForAnInvalidField()
+    {
+        $result = Value::coerceValue(['foo' => 'abc'], $this->testInputObject);
+        $this->expectError($result, 'Expected type Int at value.foo; Int cannot represent non 32-bit signed integer value: abc');
+    }
+
+    /**
+     * @it returns multiple errors for multiple invalid fields
+     */
+    public function testReturnsMultipleErrorsForMultipleInvalidFields()
+    {
+        $result = Value::coerceValue(['foo' => 'abc', 'bar' => 'def'], $this->testInputObject);
+        $this->assertEquals([
+            'Expected type Int at value.foo; Int cannot represent non 32-bit signed integer value: abc',
+            'Expected type Int at value.bar; Int cannot represent non 32-bit signed integer value: def',
+        ], $result['errors']);
+    }
+
+    /**
+     * @it returns error for a missing required field
+     */
+    public function testReturnsErrorForAMissingRequiredField()
+    {
+        $result = Value::coerceValue(['bar' => 123], $this->testInputObject);
+        $this->expectError($result, 'Field value.foo of required type Int! was not provided.');
+    }
+
+    /**
+     * @it returns error for an unknown field
+     */
+    public function testReturnsErrorForAnUnknownField()
+    {
+        $result = Value::coerceValue(['foo' => 123, 'unknownField' => 123], $this->testInputObject);
+        $this->expectError($result, 'Field "unknownField" is not defined by type TestInputObject.');
+    }
+
+    /**
+     * @it returns error for a misspelled field
+     */
+    public function testReturnsErrorForAMisspelledField()
+    {
+        $result = Value::coerceValue(['foo' => 123, 'bart' => 123], $this->testInputObject);
+        $this->expectError($result, 'Field "bart" is not defined by type TestInputObject; did you mean bar?');
+    }
+
     private function expectNoErrors($result)
     {
         $this->assertInternalType('array', $result);
         $this->assertNull($result['errors']);
+        $this->assertNotEquals(Utils::undefined(), $result['value']);
     }
 
+
     private function expectError($result, $expected) {
         $this->assertInternalType('array', $result);
         $this->assertInternalType('array', $result['errors']);
         $this->assertCount(1, $result['errors']);
         $this->assertEquals($expected, $result['errors'][0]->getMessage());
+        $this->assertEquals(Utils::undefined(), $result['value']);
     }
 }
diff --git a/tests/Validator/ValuesOfCorrectTypeTest.php b/tests/Validator/ValuesOfCorrectTypeTest.php
index dd62ebd..322d984 100644
--- a/tests/Validator/ValuesOfCorrectTypeTest.php
+++ b/tests/Validator/ValuesOfCorrectTypeTest.php
@@ -30,11 +30,12 @@ class ValuesOfCorrectTypeTest extends TestCase
         );
     }
 
-    private function unknownField($typeName, $fieldName, $line, $column) {
+    private function unknownField($typeName, $fieldName, $line, $column, $message = null) {
         return FormattedError::create(
             ValuesOfCorrectType::unknownFieldMessage(
                 $typeName,
-                $fieldName
+                $fieldName,
+                $message
             ),
             [new SourceLocation($line, $column)]
         );
@@ -581,7 +582,7 @@ class ValuesOfCorrectTypeTest extends TestCase
                 '"SIT"',
                 4,
                 41,
-                'Did you mean the enum value: SIT?'
+                'Did you mean the enum value SIT?'
             )
         ]);
     }
@@ -630,7 +631,13 @@ class ValuesOfCorrectTypeTest extends TestCase
           }
         }
         ', [
-            $this->badValue('DogCommand', 'sit', 4, 41)
+            $this->badValue(
+                'DogCommand',
+                'sit',
+                4,
+                41,
+                'Did you mean the enum value SIT?'
+            )
         ]);
     }
 
@@ -1070,7 +1077,13 @@ class ValuesOfCorrectTypeTest extends TestCase
           }
         }
         ', [
-            $this->unknownField('ComplexInput', 'unknownField', 6, 15),
+            $this->unknownField(
+                'ComplexInput',
+                'unknownField',
+                6,
+                15,
+                'Did you mean intField or booleanField?'
+            ),
         ]);
     }