A very quick (sub optimal, I have a long commute to begin) example using Mojo::DOM:

#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';
use Mojo::DOM;

my $html = '<ul><div class="txt" style="position:absolute; left:84px; 
+top:73px;"><span id="f1" style="font-size:11px;vertical-align:baselin
+e;color:rgba(0,0,0,1);">technology of S2S translation, also known as 
+Spoken Language Translation (SLT),</span></div><div class="txt" style
+="position:absolute; left:44px; top:73px;"><span id="f1" style="font-
+size:11px;vertical-align:baseline;color:rgba(0,0,0,1);">is a new appl
+ication of AI,</span></div><li>there</li><li>everyone</li></ul>
';

my $dom = Mojo::DOM->new( $html );

#  find each span tag
foreach my $id ( $dom->find('span')->each ){

    #  if the text contans the string Spoken
    if ( index($id->text, 'Spoken') > 0){
        #  replace the node within the DOM
            my $text = $id->text;
        $text =~ s/Spoken/Derp!/g;
        $id->replace( $text );
    }
}

#  print the updated DOM
say $dom->content;
[download]

Output:

<ul><div class="txt" style="position:absolute; left:84px; top:73px;">t
+echnology of S2S translation, also known as Derp! Language Translatio
+n (SLT),</div><div class="txt" style="position:absolute; left:44px; t
+op:73px;"><span id="f1" style="font-size:11px;vertical-align:baseline
+;color:rgba(0,0,0,1);">is a new application of AI,</span></div><li>th
+ere</li><li>everyone</li></ul>
[download]