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#Perl 5 + Perligata, 173 bytes

145 bytes, plus 28 for -MLingua::Romana::Perligata

Use as perl -MLingua::Romana::Perligata foo.pl; input (from stdin) and output (to stdout) are underscore-separated strings of decimal integers. Tested on Strawberry 5.20.2 with version 0.6 of Perligata, released two days ago; I don't know whether it works with Perligata version 0.50.

huic vestibulo perlegementum da.his _ scindementa da.per in his fac sic
si recidementum hoc tum II fac sic I exi cis
hoc tum _ egresso scribe

Obviously this is clear as a bell. In case it's not, run it with -MLingua::Romana::Perligata=converte instead of -MLingua::Romana::Perligata, and perl will, instead of running the script, output a translation into regular Perl:

 $_ = Lingua::Romana::Perligata::getline (*STDIN );
 @_ = split ( '_');
for $_ (@_) {if ( ($_ % 2)) {exit ( 1)}
print (STDOUT $_, '_')}

Golfing notes:

  • It seems from the documentation that ultimus si recidementum hoc tum II fac. would work instead of si recidementum hoc tum II fac sic ultimus cis, saving 7 bytes. But it doesn't (it gives a "iussa absentia" error).
  • Undocumented (but unsurprising), you don't need a space after ..
  • (Also unsurprising,) scinde doesn't need a second argument, and uses hoc. Alas, exi needs an argument.
  • Instead of huic vestibulo perlegementum da, I tried -pMLingua::Romana::Perligata, but couldn't get it to work.

Just for kicks (although this whole answer was just for kicks):

  • After cleaning it up to Huic vestibulo perlegementum da. His lacunam scindementa da. Per in his fac sic si recidementum hoc tum II fac sic I exi cis. Hoc tum lacunam egresso scribe cis., Google Translate gives This court perlegementum grant. His gap scindementa grant. 2 By that time, do so in the following 1, Go out and do so if recidementum on this side. This was the gap as soon as write on this side..