Changing every word on mouseover

I need to change every word in a paragraph of text by synonyms or alternate words. Like a mutating text that changes under the mouse pointer when goes over any of the word. The idea is to have lists of adjectives, nouns, verbs, etc. When the mouse is over any word the script will find the word in one of the list and will change it for another one in that list. Any ideas?

I tried some simple scripts to change a whole phrase or word but now I need to be able to change any individual word.

UPDATE: I put some of the code. I could load a list of words into an array and enclose every word into a span. The thing is that I want to do is to change every word with a random word from the array. The objective of all this is to have several arrays (loading from different txt lists) and to change every word for another of each list. e.g.: if the word is a noun (because it finds the word in the array nouns) it changes it for another word in that list.

Thanks a lot for any help!

<html>
<head>

<style>

    body {
        font-size:30px;
    }    
</style>    
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js" type="text/javascript"></script>


<script type="text/javascript"> 
// set this somewhere outside of the $.get callback.
// no need to pass it in as it will be available in that scope.
var data_array = [];

$.get('sustantivos.txt', function(data) {
    var lines=data.split('\n');
    for (var i=0; i<lines.length;i++){
        var item=lines[i];
        data_array.push([0,item]); // modify data_array here
    }
    // no need to return it
});

    console.log(data_array);

var n=0;     
$(function() {

    // wrap words in spans
        $('p').each(function() {

            var $this = $(this); 
            $this.html($this.text().replace(/\b(\w+)\b/g, "<span id='w0'>$1</span>"));


        });

        $('span').each(function() {
            n++;
            var newID='w'+n;
            $(this).attr('id',newID);
        });

        // bind to each span
        $('p span').mouseenter(
            function() { $('#word').text($(this).css('background-color','#ffff66').text()); },
            function() { $(this).text(data_array[Math.floor(Math.random()*data_array.length)][1]); $(this).css('background-color',''); }
        );
    });


</script>

</head>

<body>

<p>Each word will be wrapped in a span.</p>
<p>A second paragraph here.</p>

</body>
</html>