Dierdre is an unseen alien girl whom Seamus Harper knew, and was flirting with on one of his supply runs to bring parts back to the Andromeda Ascendant. Beka Valentine was teasing Harper about the fact that he could not even speak her language (Celtic, Beka thinks), and yet was apparently "in love" with her, when the Perseid Renvik entered the Eureka Maru's outer airlock. Rommie correctly identifies Dierdre's dialect when a suddenly fluent Harper uses Irish Gaelic, an adapted form, to come on to her a little later, following it up with French and Perseid, and then several more languages. ("Harper 2.0")