Pla ce bo,
Who is there, who?
Di le xi,
Dame Margery;
Fa, re, my, my,
Wherfore and why, why?
For the sowle of Philip Sparowe
That was late slayn at Carowe,


Latin placebo 'I shall please'; Latin dilexi 'I have loved, appreciated'.

Quote:
Skelton’s originality is more evident in Phyllyp Sparowe, a poem addressed to Jane Scroupe, a young lady who was a pupil of the black nuns at Carow, and whose pet sparrow had been killed by a cat. The bird is pictured at great length and its mistress’s grief described in exaggerated language. All the birds under the sky are summoned to the burial, and each one there is appointed to its special office.


[From Cambridge History of English and American Literature III.iv.7.]
Boards can be tables (as in side-board). Also of note that, in the OED1, there's an entry for bourd (sometimes borde) 'jest, jape' from French bourde. And, covered could mean hidden at the time.


Ceci n'est pas un seing.