Just remove the code from the structure.pdt /app/views/client/bootstrap/structure.pdt
look for:
elseif ($this->Html->ifSet($show_language) && $this->Html->ifSet($languages) && count($languages) > 1) {
?>
<div class="top-nav pull-right">
<?php
$this->Form->create($this->client_uri . 'main/setlanguage/', ['id' => 'language_selector']);
$this->Form->fieldHidden('redirect_uri', $this->Html->ifSet($request_uri));
$this->Form->fieldHidden('language_code', Configure::get('Blesta.language'), ['id' => 'language_code']);
$this->Form->end();
?>
<ul>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown"><?php $this->Html->_($languages[Configure::get('Blesta.language')])?> <b class="caret"></b></a>
<ul class="dropdown-menu dropdown-menu-right" id="language_switcher">
<?php
foreach ($languages as $code => $language) {
?>
<li class="language_code" language_code="<?php echo $this->Html->safe($code);?>"><a href="#"><?php echo $this->Html->safe($language);?></a></li>
<?php
}
?>
</ul>
</li>
</ul>
</div>
<?php
}
?>