Na, na, black sheep have you any wool,
Ba, ba, Shepherd, yes, three bags full.

The sheep sheerers name in old man Dan,
His wife her name is sweet, young Naan.

He is too rough with his sheep, a bad habit,
Another one escapes till he can nab it

Naan is inside preparing Dans favorite meal of greek Mulvba,
which contains lamb shanks, red onions and fresh picked nabalus alba.
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Here are the first four in my dictionary of the O's

oak, oar, oasis, oat

These should be a breeze after those N's, tough words, geesh!!!