Morse code in Cayo Largo del Sur, Cuba is coded as "UCL", and UCL in Morse code is transmitted on its radio frequency. In some countries, during periods of maintenance, the facility may radiate a T-E-S-T code () or the code may be removed which tells pilots and navigators that the station is unreliable. In Canada, the identification is removed entirely to signify the navigation aid is not to be used. In the aviation service, Morse is typically sent at a very slow speed of about 5 words per minute. In the U.S., pilots do not actually have to know Morse to
History of the alphabet added in the Arabic alphabet include these (except for , which survives as a separate phoneme in Ge'ez ሠ): One modern national alphabet that has not been graphically traced back to the Canaanite alphabet is the Maldivian script, which is unique in that, although it is clearly modeled after Arabic and perhaps other existing alphabets, it derives its letter forms from numerals. Another is the Korean Hangul, which was created independently in 1443. The Osmanya alphabet was devised for Somali in the 1920s by Osman Yusuf Kenadid, and the forms of its consonants appear to be complete innovations. Among alphabets