Use the getText utility function provided by Sizzle.

src/manipulation.js

@@ -36,20 +36,7 @@ jQuery.fn.extend({
 			return this.empty().append( (this[0] && this[0].ownerDocument || document).createTextNode( text ) );
 		}
 
-		var ret = "";
-
-		jQuery.each( this, function() {
-			// Get the text from text nodes and CDATA nodes
-			if ( this.nodeType === 3 || this.nodeType === 4 ) {
-				ret += this.nodeValue;
-
-			// Traverse everything else, except comment nodes
-			} else if ( this.nodeType !== 8 ) {
-				ret += jQuery.fn.text.call( this.childNodes );
-			}
-		});
-
-		return ret;
+		return jQuery.getText( this );
 	},
 
 	wrapAll: function( html ) {

src/sizzle-jquery.js

@@ -2,5 +2,6 @@ jQuery.find = Sizzle;
 jQuery.expr = Sizzle.selectors;
 jQuery.expr[":"] = jQuery.expr.filters;
 jQuery.unique = Sizzle.uniqueSort;
+jQuery.getText = getText;
 
 return;