"Local language spam has normally been easy for users to spot as it had obviously been translated electronically," said Diego d'Ambra, chief technology officer at SoftScan.
"Spammers are realising that localisation is required if they want people to respond in some way, whether clicking on a link or purchasing goods."
SoftScan reported that November was the sixth consecutive month during which spam broke the 90 percent barrier.
Junk mail has grown considerably from 90.06 percent in June, to November's high of 96.3 percent.
At the weekends, when there is less legitimate business email, spam levels were consistently over 98 percent. The peak was 98.71 percent.
The number of viruses within email messages appears to have fallen back to levels seen before the summer, accounting for just 0.08 percent of email scanned in November.