You can detect the language being used by client in Javascript using navigator.language or navigator.userLanguage
<html>
<head>
<body>
Now you could populate using javascript
<div id="greeting">
Nothing specified
</div>
<script>
var userLang = (navigator.language) ? navigator.language : navigator.userLanguage;
document.write("Languages is " + userLang);
if(userLang=="en" || userLang=="en-US")
content = "Hello";
else if(userLang=="es")
content = "Hola";
document.write(".......content is " + content);
document.getElementById('greeting').innerHTML = content;
</script>
</body>
</html>