angular js ng-repeat directive is not working for the inner object properties

$scope.school{
              name  : "stackoverflow",
              sub   :{
                       firstlang : "kannada"
                     }
              }

For the above object pattern , the below ng-repeat is not working

<ul>
    <li ng-repeat="index in school.sub">
        first language is = {{index.firstlang}}
   </li>
</ul>

Desired result: ng-repeat should display first language is = kannada

Looking at your example it is not very clear how the school.sub data structure should look like in the end... Is it supposed to be an object (as in the example data structure) or an array (as you ngRepeat seems to suggest).

Provided that the school.sub is an object this would work: http://jsfiddle.net/pkozlowski_opensource/WXsFD/1/

<li ng-repeat="(key, value) in school.sub">first language is = {{value}}</li>

On the other hand, if you plan your sub structure to be an array the proper approach would be: http://jsfiddle.net/pkozlowski_opensource/WXsFD/2/

<li ng-repeat="index in school.sub">first language is = {{index.firstlang}}</li>

Hope that the above jsFiddles clarify how to approach both situations.