splice!

use Data::Dumper;
my $string = 'bla bla [[en:English]][[de:German]][[ga:Irish]] bla bla'
+;

my $groups = 2;
my @tmp = ($string =~ m/\[\[(en|de|ga):(.+?)\]\]/g);
my @matches;
push @matches, [splice @tmp, 0, $groups] while @tmp;

print Dumper \@matches;


$groups = 3;
@tmp = ($string =~ m/\[\[(en|de|ga):(.)(.+?)\]\]/g);
@matches = ();
push @matches, [splice @tmp, 0, $groups] while @tmp;

print Dumper \@matches;
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