Without big pipe:

<ul class="...">
<li class="...">
Content of menu block 1
</li>
<li class="...">
Content of menu block 2
</li>
<li class="...">
Content of language switcher block
</li>
<li class="...">
Content of menu block 3
</li>
</ul>

With big-pipe:

<ul class="...">
<li class="...">
Content of menu block 1
</li>
<li class="...">
Content of menu block 2
</li>
<div>
<li class="...">
Content of language switcher block
</li>
</div>
<li class="...">
Content of menu block 3
</li>
</ul>