index.html

  
 <!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.0/jquery.min.js"></script>
<body ng-app="myApp">

<div ng-controller="myCtrl">
	<form name="myForm">
    	<input type="text" ng-model="value" name="value" ng-pattern="/([\p{L}-]+)/ug">
        <span style="color:red" ng-show="myForm.value.$error.pattern">Enter alphabets or unicode characters only</span>
    <br>
    	<input type="submit" value="Submit" ng-disabled="!value">
      <br>
    </form>
</div>

<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', ['$scope', function($scope) {
	$scope.value = '';
}]);
</script>

</body>
</html>