<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>twoLanguages</title>
<link rel='stylesheet' type='text/css' href='styleButton.css'/>
</head>
<body>
<span id='lang'>Ru</span>
<br><br>
<div id='change'>
<h2>Hello</h2>
<br><br>
<p>Это я!</p>
</div>
<script src="https://code.jquery.com/jquery-1.12.4.js"></script>
<script src='scriptBtn.js' charset="utf-8"></script>
</body>
</html>