<?php
header('Content-Type: text/plain; charset="utf-8"');

function createCombinations(array $input)
{
    $head = array_shift($input);
    $tail = count($input) > 1 ? createCombinations($input) : array_shift($input);

    $combinations = [];
    foreach ($head as $left) {
        foreach ($tail as $right) {
            $combinations[] = array_merge([$left], (array) $right);
        }
    }

    return $combinations;
}

$element = [
    'vehical'  => ['vehicle', 'car'],
    'recovary' => ['recovery', 'recover', 'revary'],
    'cubs'     => ['cabs'],
];

$sentence = 'i want to recovary my vehical from the cubs';
$from = array_keys($element);

foreach (createCombinations($element) as $to) {
    echo str_replace($from, $to, $sentence), "\n";
}