TODO.txt

from https://reactos.org/wiki/Techwiki:Win32k/syscalls :
NtUserCheckImeHotKey
NtUserDisableThreadIme
NtUserGetAppImeLevel
NtUserGetImeHotKey
NtUserGetImeInfoEx
NtUserNotifyIMEStatus
NtUserSetImeHotKey
NtUserSetImeInfoEx
NtUserSetImeOwnerWindow

from https://reactos.org/wiki/Techwiki:Win32k/apfnDispatch :
fnIMECONTROL
ClientImmLoadLayout
ClientImmProcessKey

from https://reactos.org/wiki/Techwiki:Win32k/apfnSimpleCall :
NOPARAM_ROUTINE_GETIMESHOWSTATUS     _GetIMEShowStatus
NOPARAM_ROUTINE_UPDATEPERUSERIMMENABLING     UpdatePerUserImmEnabling
ONEPARAM_ROUTINE_SETIMESHOWSTATUS     xxxSetIMEShowStatus
HWNDLOCK_ROUTINE_CHECKIMESHOWSTATUSINTHRD     xxxCheckImeShowStatusInThread
????    xxxBroadcastImeShowStatusChange
TWOPARAM_ROUTINE_NLSSENDIMENOTIFY     NlsKbdSendIMENotification

and something that seems mentioned on the internet, yet undocumented: SPI_SETSHOWIMEUI .