It looks like the deal with this is that recent versions of PHP have changed the behavior of heredocs, and this has caused the language files to be retroactively-bogus.
They all need to be gone through and rewritten to deal with the new heredoc behavior.
For example, to fix this one message in the en local:
Record successfully added to relationship = "Record successfully added to "XATAFACEE"$query['-relationship']"XATAFACEQ" relationship.\n"
should be changed in lang/en.ini, to:
Record successfully added to relationship = "Record successfully added to {$query['-relationship']} relationship."
There are dozens of other places where this sort of thing is happening. =/
-D