The Sea Children - UK (1973)

Three friends - two boys and a girl - are holidaying in Malta and enjoying diving in the azure sea off the striking rock formations when one of them notices a strange-looking young boy swimming nearby. He tries to attract the boy’s attention, but to no avail, and an attempt to chase him simply loses sight of him, seemingly for good. But as luck would have it, they do manage to capture him and take him back to their home, where communication proves difficult until they realise he is speaking in a sped-up version of English. With the help of a tape recorder, they work out what he is saying, and he slows down his speech accordingly to tell them a whale of a tale…