Theories about the early formation of the rules of English grammar have been thrown into confusion by the discovery in an attic in Soho of an old manuscript bearing what are believed to be primitive song lyrics. The manuscript, which is thought to date from the early middle or late beginning of the 20th century, includes verb formations that have mystified grammarians.

"The very opening line is something of an enigma," explained Athelstan Fowlbit, Murdoch professor of creative grammar at the University of Milwall. "It runs: `Is you is or is you ain't my baby?' and I think you can already see what we are up against."

The professor went on to explain that since the line is couched in the interrogative, he deduced that the indicative forms of the first verb must be "you is is" which raises the question of which "is" is the primary and which the auxiliary verb. "This, of course," he went on, "we took to be explained by the subsequent `is you ain't' - or `you is ain't' in its indicative form, which appears to imply that the first `is' in `you is is' is the primary and the second the auxiliary - a most unusual occurrence."

Warming to his theme, he continued: "So we proceeded to line two in the hope of further enlightenment. The result, however, was precisely the converse. It goes: `The way you's actin' lately makes me doubt.' Now surely that should read: `the way you is is actin' lately makes me doubt', or possibly, `is makes me doubt', at the end.

"We were frankly bewildered, yet the third line threw up an alternative theory: `Honey, won't you be my baby, baby?' Perhaps the repetition of `is' in the verb form `you is is' is no more than a simple echolalia, grammatically cognate with the repetition of `baby' in `baby, baby'."

Yet the question remained why the "is" was repeated in "is you is my baby", while it was the "baby" in "Honey, won't you be my baby, baby?" The professor moved to the final line of the manuscript, which read: "Guess my flame in your heart done gone out."

His earlier research had indicated that a primary echolalic repetition of the auxiliary verb "to be" appeared to take precedence over the dittographic "baby, baby", yet there was no repetition at all in the conjectural last line. Not even a "did done gone out".

"It's most infuriating," said the professor, "when you come across such documents written by people who are clearly not sufficiently adept in the language they are using; but I think we can now begin to piece things together. We are speaking here of auxiliary echolalia in the interrogative and a complete conjugation of the verb `to be' that runs I am is, you is is, he is is, we, you and they are is, or possibly is are - we need more information on that latter matter.

"The first line of the song, if song it be, is a masterpiece of consistency, but I'm afraid the author made a bit of a hash of the rest of it." The professor smiled benignly, adding, "but perhaps he was under some sort of emotional strain."