"abbreviation by use of initials," 1950, from initial (n.) + -ese.
Entries linking to initialese
initial n.
"initial letter of a name or surname," 1620s, from initial (adj.) in a specialized sense "standing at the beginning of a word, sentence, etc." (1620s).
-ese
word-forming element, from Old French -eis (Modern French -ois, -ais), from Vulgar Latin, from Latin -ensem, -ensis "belonging to" or "originating in."