recursively get user input value in array values

Here is a recursive function that will do what you want. It loops through the array, looking for words that match the beginning of the string. It it finds one, it then recursively tries to find words in the array (excluding the word already matched) which match the the string after it has had the first match removed.

function find_words($string, $array) {
    // if the string is empty, we're done
    if (strlen($string) == 0) return array();
    $output = array();
    for ($i = 0; $i < count($array); $i++) {
        // does this word match the start of the string?
        if (stripos($string, $array[$i]) === 0) {
            $match_len = strlen($array[$i]);
            $this_match = array($array[$i]);
            // see if we can match the rest of the string with other words in the array
            $rest_of_array = array_merge($i == 0 ? array() : array_slice($array, 0, $i), array_slice($array, $i+1));
            if (count($matches = find_words(substr($string, $match_len), $rest_of_array))) {
                // yes, found a match, return it
                foreach ($matches as $match) {
                    $output[] = array_merge($this_match, $match);
                }
            }
            else {
                // was end of string or didn't match anything more, just return the current match
                $output[] = $this_match;
            }
        }
    }
    // any matches? if so, return them, otherwise return false
    return $output;
}

You can display the output in the format you desire with:

$wordstrings = array();
if (($words_array = find_words($string, $array)) !== false) {
    foreach ($words_array as $words) {
        $wordstrings[] = implode(', ', $words);
    }
    echo implode("<br>\n", $wordstrings);
}
else {
    echo "No match found!";
}

I made a slightly more complex example (demo on rextester):

$array = array('pro', 'gram', 'merit', 'mer', 'program', 'it', 'programmer'); 
$strings = array("programmerit", "probdjsabdjsab", "programabdjsab");

Output:

string: 'programmerit' matches:

pro, gram, merit<br>
pro, gram, mer, it<br>
program, merit<br>
program, mer, it<br>
programmer, it

string: 'probdjsabdjsab' matches:

pro

string: 'programabdjsab' matches:

pro, gram<br>
program

Update

Updated code and demo based on OPs comments about not needing to match the whole string.