use v5.12.0;
use warnings;
#use utf8;
binmode STDOUT, ":utf8";

print my $s = "\N{LATIN SMALL LETTER S WITH CARON}i\N{LATIN SMALL LETTER C WITH CARON}";
say " is text" if utf8::is_utf8($s);

for my $i (0 .. 2) {
    print my $c = substr $s, $i, 1;
    say " is text" if utf8::is_utf8($c);
}