<?php
$re = '/(")([^"]+)(")/';
$str = 'The nice man said "How\'s things today" and I replied "All is good thanks".';
$subst = '<i class="fa fa-quote-left" aria-hidden="true"></i>\\2<i class="fa fa-quote-right" aria-hidden="true"></i>';
echo preg_replace($re, $subst, $str);
The nice man said <i class="fa fa-quote-left" aria-hidden="true"></i>How's things today<i class="fa fa-quote-right" aria-hidden="true"></i> and I replied <i class="fa fa-quote-left" aria-hidden="true"></i>All is good thanks<i class="fa fa-quote-right" aria-hidden="true"></i>.
Output for 8.3.5
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
The nice man said <i class="fa fa-quote-left" aria-hidden="true"></i>How's things today<i class="fa fa-quote-right" aria-hidden="true"></i> and I replied <i class="fa fa-quote-left" aria-hidden="true"></i>All is good thanks<i class="fa fa-quote-right" aria-hidden="true"></i>.