Alright, thanks, lcfirst works well, but I'll be darned if I can cobble the whole thing together yet. I want now to insert 'Fear of' at the beginnning of the sentence, and I can't accomplish it. It makes no sense to me why it doesn't appear while the numbered match variables do:

$ ./fears1.pl
enter basename for file
rt2
returned was 
 0. dying exists because it's everyone's greatest terror, likely laden
+ with pain.

1. abject poverty exists because my earning power has been decreasing 
+and a regime is on the ascendance that wants to crush my class.

2. being homeless exists because it's awful and the result of 1.

3. cancer, disease exists because it runs in the family and can happen
+ spontaneously with appreciable probability. it's expensive.


$
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The caller has changed a bit, but the substitution happens here:

sub pop_texts {
  use strict;
  use 5.010;
  use File::Slurp;

  my ($rvars) = shift;
  my %vars    = %$rvars;
  my @fears   = read_file( $vars{fears} );
  my @causes  = read_file( $vars{causes} );
  for (@fears) {
    s/\s+$/ /;
    $_ = lc($_);
    s/^(\d+\. )(.) /$1 Fear of $2/;
  }
  for (@causes) {
    s/^\d+\./exists because/;
    $_ = lc($_);
  }

  #say "causes are @causes";
  my $text1 = '';
  for my $i ( 0 .. $#causes ) {
    $text1 = $text1 . $fears[$i] . $causes[$i] . "\n";
  }
  my $reftext = \$text1;
  return $reftext;
}
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I tried putting it in single quotes to no avail....