Here you go -- 
use strict;
use warnings;

my $variable = join("", <DATA>);

my @num = qw|zero one two three four five six seven eight nine|;

$variable =~ s/(\d)/$num[$1]/g;
print  "$variable";
__DATA__
This is 1 great time 2 have a 3 way 4some.
When 5 and 6 together make 11.
Some 8 or 9 of us will see that.

[download]
Output: 
This is one great time two have a three way foursome.
When five and six together make oneone.
Some eight or nine of us will see that.

[download]
Update:Thanks JavaFan(++) for the heads-up on \d - My education continues.
cdarke (See his note below) - yes - I used join because the O.P did. As you point out, it is completely unnecessary.

     Syntactic sugar causes cancer of the semicolon.        --Alan Perlis

In reply to Re: Help with Regular Expressions and Perl by NetWallah
in thread Help with Regular Expressions and Perl by vc859

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