Douglas Harper's Etymology Dictionary
1895, from cable in the telegraphic sense + -ese as a language name suffix. "Since cablegrams had to be paid for by the word and even press rates were expensive the practice was to affix Latin prefixes and suffixes to make one word do the work of several" [Daniel Schorr], such as exLondon and Londonward to mean "from London," "to London" (non-Latin affixes also were used). Hence the tale, famous in the lore of the United Press International, of the distinguished but harried foreign correspondent who reached his breaking point and wired headquarters UPSTICK JOB ASSWARD. Its economy and expressive power fascinated Hemingway in his newspapering days.
Usage examples of "cablese".
The cablese, the bad typing, and the copy-reading made it just about unintelligible to an outsider.