Edit in JSFiddle

<html ng-app="app" ng-controller="MyCtrl">
    <label>{{msg | myFilter : "ㅁㄴㅇㄹ"}}</label>
</html>
angular.module('app', [])
.filter("myFilter", function() {
    return function(text, param) {
        return text + param;
    }
})
.controller("MyCtrl", function($scope) {
    $scope.msg = "hello";
});