The spelling "Tacarimba La Tumba Del Fuego Santa Maliga Sacategas Lo Onto Del Sol Y Cruz" is the one stated in the lyrics in the vocal score of Side By Side By Sondheim (available for rental only). This version of the song, however, misspells Llanfair PG (presumably to approximate the pronunciation), and has the lyric "...today's the last I'll be spreading" rather than "spending". It would seem, therefore, that this source cannot be considered canonical. This rendering of the place name does accord with Millicent Martin's recording on the Side By Side By Sondheim cast album, however.

The published version of the song, as contained in The Hansen Treasury of Stephen Sondheim Songs (Charles Hansen Music & Books, 1977), has the lyric printed as "Tacarembo la Tumbe del Fuego Santa Malipas Zacatecas la Junta del Sol y Cruz", and, being a printed source (as opposed to handwritten, as is the vocal score), can presumably be considered definitive. Linda Lavin's pronunciation on the original cast recording of The Mad Show (for which the song was written) follows this spelling, which would suggest that the printed version is correct.

As it is a fictional place name, however, any discussion of "correct" spelling/pronunciation is an academic one, at best.