Did this ever get solved? I have same OSD menu problem. The only menu that opens is the input menu that lets me select one of the three inputs (no matter which button I press). Toggle switch does let me back out of menu. My language is fine. Update=Resolved- I was able to get the R13 working later in the day and was able to flash the new bios. Once the the computer was running and sending video to the monitor, the full OSD menu was available. 
I recently purchased a AW3821DW monitor and the only option I am allowed to adjust is the input. OSD does not come up and all the characters are in Chinese. Is there a way to reset to factory?
AW3821DW, can only change Input Source, language issue