OUR FIRST REACTION was that Alfred E. Kahn, chairman of the Civil Aeronautics Board, must be very new to government.No one with much bureaucratic experience, we thought, would bother to write a memo like the one Mr. Kahn sent around the CAB this month. Announcing "an abhorrence of the articifial and hyper-legal language that is sometimes known as bureaucratese or gobbledygook," Mr. Kahn asked the CAB staff, "please, to try very hard to write board orders and, even more so, drafts of letters for my signature, in straightforward, quasi-conversational, humane prose - as though you are talking to or communicating with real people."

Mr. Kahn likes language that can bear being read aloud. Don't say "hereinabove," he pleaded, when "above" will do. Don't write "regarding" instead of about." Don't use the passive voice to fudge a statement. Don't use the passive voice to fudge a statement. Don't be pompous; do be more precise. The words "data" and "criteria" are plural, the chairman wrote, while "for at least from the 17th through most of the 20th century, 'presently' meant 'soon' or 'immediately' and not 'now.'" Mr. Kahn's list - which was reprinted in this newspaper's business section on Sunday - did omit one of our major peeves, the constant use of "impact" as a verb. But he made up for that by leveling special scorn at "the rampant misuse of 'hopefully.'"

It is a fine initiative. And we were even more impressed when we found out that Mr. Kahn, while brand-new at the CAB, is not a novice in the world of gobbledygook. He is a veteran economist, an academic (Cornell University) and former chairman of the New York Public Service Commission. Thus he has worked for years in fields not noted for brisk or bell-like prose. If that experience has not daunted him, perhaps he can really reduce the muzziness of CAB-speak. It won't be easy; even President Carter has had to trim some of his early promises about bringing bureaucratese under control. The battle is always worth fighting, though. We hope Chairman Kahn will keep at it and that the results will be visible, if not now, at least presently.