If anyone's curious, in Holmes' own words on the matter...
“Regarding the Landless Twins: Helena and Neville hail from Ceylon, and were, in Mr. Dickens’ original novel, colonialists who, save for their tans, were quite similar in dress and character to any English youths. However, the Music Hall Royale has seized upon and misinterpreted this one bit of geographical information and made them into picturesque, exotically-garbed orientals. Keep in mind that the Music Hall’s knowledge of the Eastern world comes largely from ignorance and penny novels, from the labels on crates of spice and teas, from the Arabian Nights, and from decorative screens and prints in Victorian parlors. Therefore, no attempt need or should be made to replicate a true Hindu accent or wardrobe; this is a polyglot East, and Helena’s accent should be a compendium of Oriental cliches, or, as Janet Conover puts it herself, ‘somewhat geographically untraceable.’ Neville is a proud, hot-tempted, well-educated young man, more an exiled prince than a servile Gunga Din.”
"Art, in itself, is an attempt to bring order out of chaos."-Stephen Sondheim