in the code below i have a bug (maybe more than one). i was wondering if anyone could help. i have the output below
thank you 
Word provided by the user is:
Hello world
converted to lower case: hello world
hello world
string passed to translate() is: hello world
Array ( [0] => hello [1] => world ) explode() passed function
value: hello
Warning: implode() [function.implode]: Invalid arguments passed in /users/... on line 42
temp string is :
ay
y
value: world
Warning: implode() [function.implode]: Invalid arguments passed in /users/... on line 42
temp string is :
ay
y
The translated word/sentence into Pig Latin is: y
<?php
echo "Word provided by the user is: ".$_POST['word']."<br>";
$sentence = $_POST['word'];
$sentence = "Hello world";
echo $sentence."<br>";
$sentence = strtolower($sentence);
echo "converted to lower case: ".$sentence."<br>";
$cleaned_sentence = clean_string($sentence);
echo $cleaned_sentence."<br>";
$translated = translate($cleaned_sentence);
echo "The translated word/sentence into Pig Latin is: ".$translated."<br>";
function clean_string($sentence_to_be_cleaned) {
$bad_characters = "[^a-zA-Z]";
$new_sentence = ereg_replace($bad_characters, " ", $sentence_to_be_cleaned);
return $new_sentence;
}
function translate($string_to_translate)
{
// separating a sentence passed into individual words to translate into Pig Latin
echo "string passed to translate() is: ".$string_to_translate."<br>";
$word = explode(' ', $string_to_translate);
print_r ($word);
echo "explode() passed function <br>";
// this regex will be used to check if the first letter is vowel or not
$reg_expression = '(a|e|i|o|u)';
foreach($word as $key=>$value)
{
echo "value: ".$value."<br>";
$temp_str = implode('',$value);
echo "temp string is : ".$temp_str."<br>";
//if 1st letter of a word is a vowel
if(check_regex($reg_expression, substr($temp_str,0,1)) == TRUE)
{
echo $word[i].'`yay';
}
// else - 1st letter is a consonant
else
{
$consonant = substr($temp_str,0,1);
echo $consonant."<br>";
$new_word = $temp_str.$consonant."ay";
echo $new_word."<br>";
$new_word = substr_replace($new_word, "", 0, 1);
echo $new_word."<br>";
}
}
return $new_word;
}
function check_regex($myregex, $mystring) {
if (ereg($myregex, $mystring)) {
return TRUE;
}
else {
return FALSE;
}
}
?>