A function that transforms greek characters to english (greeklish).

greeklish.php

<?php
// Based on http://www.freestuff.gr/forums/viewtopic.php?p=194579#194579
function make_greeklish($text) {
  $expressions = array(
  	'/[αΑ][ιίΙΊ]/u' => 'e',
	'/[οΟΕε][ιίΙΊ]/u' => 'i',
	'/[αΑ][υύΥΎ]([θΘκΚξΞπΠσςΣτTφΡχΧψΨ]|\s|$)/u' => 'af$1',
	'/[αΑ][υύΥΎ]/u' => 'av',
	'/[εΕ][υύΥΎ]([θΘκΚξΞπΠσςΣτTφΡχΧψΨ]|\s|$)/u' => 'ef$1',
	'/[εΕ][υύΥΎ]/u' => 'ev',
	'/[οΟ][υύΥΎ]/u' => 'ou',
	'/(^|\s)[μΜ][πΠ]/u' => '$1b',
	'/[μΜ][πΠ](\s|$)/u' => 'b$1',
	'/[μΜ][πΠ]/u' => 'mp',
    	'/[νΝ][τΤ]/u' => 'nt',
	'/[τΤ][σΣ]/u' => 'ts',
	'/[τΤ][ζΖ]/u' => 'tz',
	'/[γΓ][γΓ]/u' => 'ng',
    	'/[γΓ][κΚ]/u' => 'gk',
    	'/[ηΗ][υΥ]([θΘκΚξΞπΠσςΣτTφΡχΧψΨ]|\s|$)/u' => 'if$1',
   	'/[ηΗ][υΥ]/u' => 'iu',
    	'/[θΘ]/u' => 'th',
    	'/[χΧ]/u' => 'ch',
    	'/[ψΨ]/u' => 'ps',
    	'/[αά]/u' => 'a',
	'/[βΒ]/u' => 'v',
    	'/[γΓ]/u' => 'g',
    	'/[δΔ]/u' => 'd',
    	'/[εέΕΈ]/u' => 'e',
    	'/[ζΖ]/u' => 'z',
    	'/[ηήΗΉ]/u' => 'i',
	'/[ιίϊΙΊΪ]/u' => 'i',
	'/[κΚ]/u' => 'k',
	'/[λΛ]/u' => 'l',
	'/[μΜ]/u' => 'm',
	'/[νΝ]/u' => 'n',
	'/[ξΞ]/u' => 'x',
	'/[οόΟΌ]/u' => 'o',
	'/[πΠ]/u' => 'p',
	'/[ρΡ]/u' => 'r',
	'/[σςΣ]/u' => 's',
	'/[τΤ]/u' => 't',
	'/[υύϋΥΎΫ]/u' => 'i',
	'/[φΦ]/iu' => 'f',
	'/[ωώ]/iu' => 'o',
	);
	
	$text = preg_replace( array_keys($expressions), array_values($expressions), $text);
	return $text;
}
?>