<!DOCTYPE html>
<html>
<head>
<style>
[lang|=en] {
    background: yellow;
}

</style>
</head>
<body>

<p lang="en">Hello!</p>
<p lang="en-us">Hi!</p>
<p lang="en-gb">Ello!</p>
<p lang="us">Hi!</p>
<p lang="no">Hei!</p>

<p><b>Note:</b> For [<i>attribute</i>|=<i>value</i>] to work in IE8 and earlier, a DOCTYPE must be declared.</p>

</body>
</html>