Tiempo transcurrido en español

time_elapsed_string.func.php

function time_elapsed_string($datetime, $full = false) {
        $now = new \DateTime;
        $ago = $datetime;
        $diff = (array) $now->diff($ago);

        $diff['w'] = floor($diff['d'] / 7);
        $diff['d'] -= $diff['w'] * 7;

        $string = array(
            'y' => 'año',
            'm' => 'mes',
            'w' => 'semana',
            'd' => 'dia',
            'h' => 'hora',
            'i' => 'minuto',
            's' => 'segundo'
        );
        foreach ($string as $k => &$v) {
            if ($diff[$k]) {
                $v = $diff[$k] . ' ' . $v . ($diff[$k] > 1 ? (($k == 'm')?'es':'s') : '');
            } else {
                unset($string[$k]);
            }
        }

        if (!$full) $string = array_slice($string, 0, 1);
        return $string ? 'Hace ' . implode(', ', $string): 'Ahora';
    }