The answer is here: What is the best way to add options to a select from an array with jQuery?

Loop through your languages in a for loop, and use the code in that answer above.

var languages = [
  'AFRIKAANS : af',
  'ALBANIAN : sq',
  'AMHARIC : am',

]

$.each(languages,function(index,elem){
    $("#langsel").append(

    $("<option/>").val(elem.split(':')[1]).text(elem.split(':')[0])

    );
});

fiddle http://jsfiddle.net/3dFgg/

The quickest (to type) way to do it would be to first build the HTML string, and then insert it into the <select>:

var languages = { /* ... */ },
    str = '',
    hop = Object.prototype.hasOwnProperty,
    x;

for (x in languages) {
    if (hop.call(languages, x)) {
        str += '<option value="' + languages[x] + '">' + x + '</option>';
    }
}
document.getElementById('langsel').innerHTML += str;

You could do something like this:

var sel = $("#langsel");
var html = "";
var items = Languages;
html =  $("<option></option>").text("Select a Language").val(""); 
sel.append(html);
html = "";
for (var index in items) {
    html = $("<option></option>").text(index).val(items[index]);
    sel.append(html);
    html = "";
}    

jsFiddle http://jsfiddle.net/FXta5/

You can certainly do this manually, but for fun, this is the sort of thing jQuery Templates are designed to do. The {{each}} tag will let you iterate over an array or object, building some dynamic HTML as you go.

First set up the template:

<script id="optionTemplate" type="text/x-jquery-tmpl">
    {{each(lang,abbrev) $data}}
    <option value="${abbrev}">${lang}</option>
    {{/each}}
</script>

Here's the empty HTML <select> to be filled with new <option> tags:

<select id="langsel" name="selector">
    <option value="">Select a language</option>
</select>

Your language object:

var langs = {
    'AFRIKAANS': 'af',
    'ALBANIAN': 'sq',
    'AMHARIC': 'am',
    'ARABIC': 'ar',
    'ARMENIAN': 'hy',
    'AZERBAIJANI': 'az'
};

Then the easy part:

$("#optionTemplate").tmpl(langs).appendTo("#langsel");

Here's a working example: http://jsfiddle.net/redler/nHtH3/