Ciarili was referring to the h in Cailleach Dhubh. Moll Dubh is not lenited (or aspirated) nor is Bean Dubh (lenition is often abandoned when the letters d,n,t,l,s follow one another), but Cailleach Dhubh is, according to both Ó Domhnaill's Irish dictionary and Dwelly's Scottish Gaelic dictionary and the more modern "Brigh nam Facal". The word "cailleach" is grammatically feminine and that accounts for the lenition of the adjective following it. (However it is true that some words may be treated grammatically as feminine in one dialect and as masculine in another)

The Irish dictionary cites "Cailleach Dhubh" and "Cailleach Mhuire" (woman of Mary) as historical, old terms for a nun. Both dictionaries give "cailleach dhubh" for the cormorant as well, though in my experience sgarbh is the more commonly used name in Scotland.

Another interesting name given in Dwelly is "cailleag-beag-an-earbaill" (the little woman of the tail) for the long-tailed tit (titmouse, a bird!), also called "cìochan fada". In Irish the long-tailed tit would be called "meantán earrfhada", but Dwelly translates "meantan" as snipe, a very different sort of bird. I've also come across gocan for a tit in Scotland, though it seems to be a name applied to various small birds. Cìochan really intrigues me, as cìoch means breast and I didn't think we were talking about that kind of tit. It reminds me of a local hotel which used to have a blue dome on its roof and was jokingly called the "blue tit". "Tit" for a small bird may be of Viking origin also, as in the Icelandic titlinr.

An older Irish dictionary, Dineen's, does have an entry for "scarbh", translated as "cormorant"; but the only meaning given for "scarbh" by Ó Domhnaill is a "scarf". According to the Concise Oxford Dictionary of English Etymology (1996 edition), "cormorant" comes from the medieval Latin "corvus marinus", a sea raven.

Leann (or leanna) is ale (though the word is sometimes used to refer to other types of liquid), leann dubh is the black stuff: porter, stout (for example Guinness)