Rawley Grau, a former colleague, posed a question on Facebook about a New York Times usage. Why, he wondered, does The Times use the term spokeswoman rather than spokesperson?
One simple answer is that news style guides are conservative and reluctant to change. They are prissy about vulgar language. Ms. as a courtesy title for women and gay for homosexual were in widespread use long before their admission to the sacred precincts of The New York Times Manual of Style and Usage and The Associated Press Stylebook.
In 1986, when I began work on the copy desk at The Sun, the AP Stylebook said flatly, "spokesman, spokeswoman But not spokesperson." Today it says grudgingly, "Use spokesperson if it is the preference of an individual or an organization." My copy of the Times manual dates from 1999, but it would not surprise me to learn that the prohibition rests unchanged there as well.
Spokesperson, like chairperson, came into vogue with the attempt to avoid sexist language and sexist assumptions—and the AP Stylebook now grudgingly allows chairperson "if preferred by an organization." Hell, it even allows chair for the person's title, though I believe some copy editors still gag at it.
But there are some nuances to be observed, and if stylebook editors ever listened to my advice, I would suggest an entry along these lines.
spokesman, spokesperson, spokeswoman [alphabetical, don't you know] Spokesperson is appropriate in all cases, particularly when the person's gender is unknown or irrelevant. If spokesman is used, spokeswoman must also be used. Do not use spokesperson for women alone.