Outlook Express Date Field Format

The affected user sends out e-mail in English. The recipient receives the
message with no encoding problems. However, if the original sender views the
message he sent that's stored in the Sent Items folder, the date field is in
Spanish. In addition, every mail the affected user receives shows the date in
Spanish. Can anyone think of a reason for this? I've compared Options settings
with a "normal" OLEXP on another system and they are the same. Obviously, this
problem is not causing a great deal of difficulty, but it is a problem for the
affected user since his Spanish is not up to snuff. ;~)

Thanks for any help you may provide.