<?php

error_reporting(-1);
mb_internal_encoding('utf-8');

$text = "Кажется, нас обнаружили! Надо срочно уходить отсюда, пока не поздно. Бежим же скорее!";

function makeFirstLetterUppercase($text) {
    $firstUp = mb_strtoupper(mb_substr($text, 0, 1)) . mb_substr($text, 1, null);
    return $firstUp;
}

function makeYodaStyleText($text) {
    $lowText = mb_strtolower($text);
    $sentence = preg_split("/[.!?]/u", $lowText, 0, PREG_SPLIT_NO_EMPTY);
        foreach ($sentence as $sentences) {
            $clearText = preg_replace("/[,;]/u", "", $sentences);
            $words = preg_split("/\\s/u", $clearText, 0, PREG_SPLIT_NO_EMPTY);
            $reverse = array_reverse($words);
            $resultString = implode(" ", $reverse) . ".";
            $text = makeFirstLetterUppercase($resultString);
            $yodaText[] = $text;
    }
    $port = implode(" ", $yodaText);
    return $port;
}

$yodaStyle = makeYodaStyleText($text);
echo $yodaStyle;