Advanced PHP loop

Please, don't do this. - Make an API call to a PHP backend producing the data you need. - Using either out of the box functions such as $.ajax from jQuery or other prebuilt frameworks will help you achieve this.

If you still want to go down the line of dynamically doing this (your question) - remove var_dump - which is ultimately dumping the type and other details (as it should) and use foreach (key, value) which will help you generate what you need. - But rather going down this dodgy route I'd recommend you take a look at how to serve an API using Laravel or other frameworks.

You could pass data from PHP to JS with JSON.
From PHP, you can use json_encode():

echo json_encode($translation);

And in your JS use JSON.parse():

var obj = JSON.parse('{"key":value}');

You can then do:

<?php
$allLangs = $this->params->getLanguages;
$json = json_encode($allLangs);
?>
<script>
    var Lang = JSON.parse('<?php echo $json; ?>');
</script>

As others here have already mentioned; it is a bad idea to dynamically create your javascript like this - I would instead use JSON to serialize and deserialize the data. Anyway, if you insist on dynamic creation; it'll probably be something along the lines of;

var Lang = {
<?php
  $allLangs = $this->params->getLanguages;
  foreach ($allLangs as $allLang) {
    echo $allLang->lang_code . ': {';
        foreach ( $translationsall as $translation ) {
            $total_words_to_translate = count($translation);
            for($i = 0; i <= $total_words_to_translate; $i++){
                if ( $translation['it_text'] == 'txtUserName' ){
                    print("txtUserName: ".$translationsall[$i]);
                }
                if ( $translation['it_text'] == 'txtLogout' ){
                    print("txtLogout: ".$translationsall[$i]);
                }
            }
        }
     echo '},';
     echo "\r\n";
    }
?> }

Its somewhat hard to determine the exact code when we don't know the structure / naming conventions of your database / variables.

Use json_encode:

var Lang = <?php
  $all_langs = $this->params->getLanguages();
  echo json_encode($all_langs);
?>;

Not sure how close I am with the data definitions, but I've included them so you can see what I'm assuming and hopefully be able to adjust it to your needs.

The way it works is that it starts at the beginning of $translationsall array and assumes that the $allLangs array is in the same order as the entries ( so in this case the dnk and then the eng values). These it then populates into the output under the language key, with it_text as the key and it_name as the translation.

$translationsall = [["it_text" => "txtLogout", "it_name"=>"Afslut"],
    ["it_text"=> "txtLogout", "it_name"=> "Logout"],
    ["it_text" => "txtLogout2", "it_name"=>"Afslut2"],
    ["it_text"=> "txtLogout2", "it_name"=> "Logout2"]
];

$allLangs = [ (object)["lang_code"=> "dnk"], (object)["lang_code"=> "eng"] ];
$countTrans = count($translationsall);
$out = [];
$i = 0;
while( $i < $countTrans )    {
    foreach ( $allLangs as $language )  {
        $out[$language->lang_code][$translationsall[$i]["it_text"]] = $translationsall[$i]["it_name"];
        $i++;
    }
}

echo json_encode($out, JSON_PRETTY_PRINT);

This prints out

{
    "dnk": {
        "txtLogout": "Afslut",
        "txtLogout2": "Afslut2"
    },
    "eng": {
        "txtLogout": "Logout",
        "txtLogout2": "Logout2"
    }
}

You can try with echo see bellow code :

var Lang = {
<?php
  $allLangs = $this->params->getLanguages;
  foreach ($allLangs as $allLang) :
    echo $allLang->lang_code . ': ';
    echo '{';
    foreach ( $translationsall as $translation ) :
        if ( $translation['it_text'] == 'txtUserName' and $translation['itl_lang_code '] == $allLang->lang_code) :
    echo "txtUserName:'".$translation['it_text']."',txtLogout:'".$translation['it_name']."' ";
          endif;
    endforeach;
       echo '}';
    echo '},';
    echo "\r\n";
    endforeach;
?>
          }