The 140 character limit was chosen based on sending 8bit SMS messages. If it was chosen from an English speaking viewpoint, they could have chosen to base it on

The 140 character limit was chosen based on sending 8bit SMS messages. If it was chosen from an English speaking viewpoint, they could have chosen to base it on GSM 7bit SMS, which would allow 160 characters. Was the default SMS 8bit in the US at the time or? Asian languages would require UCS2 encoded SMS messages, which can contain 70 characters as far as I remember.