<?php
$error = false;
$original_value = 'hello world 進撃進撃 lorem ipsum';
$originalLenght = strlen($original_value); // get the string length
$parts = explode(" ", $original_value);
 
 
$newValue = "hello world newword";
$newLenght = strlen($newValue); // get the new string length
$newParts = explode(" ", $newValue);
 
//Check if the new sentence contains new words using in_array
foreach($newParts as $newWord){
if (!in_array($newWord, $parts)) {
	$error = true;
}
}
 
//Check if the size of the new sentence is > than the original
if($newLenght > $originalLenght OR $error){
	echo "Invalid Sentence";
}else{
	echo "Valid Sentence";
}

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