Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide

NATLANG

The NATLANG option specifies the national language to be used for run-time messages. Message translations are provided for Japanese and mixed-case U.S. English. NATLANG also determines how the message facility formats messages.

Read syntax diagramSkip visual syntax diagram               .-ENU-.
>>-NATLANG--(--+-JPN-+--)--------------------------------------><
 
JPN
This is a 3-character id specifying Japanese. Message text can be a mixture of SBCS (single-byte character set) and DBCS (double-byte character set) characters.
ENU
This is a 3-character id specifying mixed-case U.S. English. Message text is made up of SBCS characters and consists of both upper and lowercase letters.

USAGE: NATLANG(ENU)

Run-time option and storage reports, as well as dump output, are written only in mixed-case U.S. English.

If you specify a national language that is unavailable on your system, the default is used.

Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide