/(?<=\p{Alpha}),(?=\p{Alpha})/

##</code><code>##

while( $line =~ /,/g ) {
    print "Matched a comma.\n";
}

##</code><code>##

while( $line =~ m/(?:^|,)"([\p{Alpha}\s]+)"(?=,|$)/g ) {
    print "$1\n";
}

##</code><code>##

print "$_\n" for $line =~ m/(?:^|,)"([\p{Alpha}\s]+)"(?=,|$)/g;