I have found a small but nice program to change the SAP logon language on the fly without the user having to log off and log on again. This program is very useful to me on some days and I save a lot of time to test e.g. functionalities multilingual.

REPORT ZBCLNG01 .

data list like msxxlist occurs 10 with header line.

parameters p_spras like sy-langu obligatory default sy-langu.

call function 'TH_SERVER_LIST'
tables
list = list.

loop at list where host = sy-host.
set locale language p_spras.

call function 'TH_REMOTE_TRANSACTION'
exporting
tcode = space
dest  = list-name.

exit.
endloop.

It is easiest to link it to a transaction e.g. ZLAN (ZLanguage)