Sixteen British grandmothers were audiotaped reading aloud to and conversing with their grandchildren aged 1-3 years and with an adult. Data concerning vocal pitch (indicated by fundamental frequency), and rate of speech were extracted from the audiotapes by means of a Visispeech pitch extraction system. It was found that grandmothers showed raised pitch for both reading and conversing when interacting with their grandchildren, with modifications greater for conversing relative to reading. The time taken to read a story to children was also found to be significantly greater than for adult-adult speech. W ide individual variation was evident in the extent of these prosodic modifications. Both similarities and differences were noted between British 'grandmotherese' speech and British 'motherese' speech.