AngularJS Example:

HTML

<link rel="stylesheet" href="http://twitter.github.com/bootstrap/assets/css/bootstrap.css">
<div ng-app>
    <div ng-controller="LanguageController">
        <div><span>Current Language: {{language}}</span>
        </div>
        <div><span>Term 1: {{dictionary.term1}}</span>
        </div>
        <div><span>Term 2: {{dictionary.term2}}</span>
        </div>
        <div>
            <select ng-model="language" ng-change="changeLanguage(language)">
                <option ng-repeat="(key, value) in languages" value="{{key}}">{{key}}</option>
            </select>
        </div>
    </div>
</div>

JavaScript

function LanguageController($scope) {
    $scope.languages = {
        'English': {
            'term1': 'This is Term 1 in English',
                'term2': 'This is Term 2 in English'
        },
            'French': {
            'term1': 'This is Term 1 in French',
                'term2': 'This is Term 2 in French'
        },
            'Vietnamese': {
            'term1': 'This is Term 1 in Vietnamese',
                'term2': 'This is Term 2 in Vietnamese'
        }
    };
    $scope.language = 'English';
    $scope.dictionary = $scope.languages[$scope.language];

    $scope.changeLanguage = function (lang) {
        $scope.language = lang;
        $scope.dictionary = $scope.languages[lang];
    }

}