Priscilla Dunstan's Playskool Tape Recorder

Origin
Dunstan Baby Language is a claim about infantile vocal reflexes as signals, in humans. The claim is that across cultures and linguistic groups there are five sounds, each with a meaning, that are used by infants before the language acquisition period. The hypothesis was developed by Australian former mezzo-soprano, Priscilla Dunstan, and has been featured on The Oprah Winfrey Show. Dunstan's claims have not been scientifically validated.

Effects
Having an infant speak through one microphone translates their babble in a way that is understandable to whoever holds the other microphone, and vice versa, allowing two parties to have a conversation, albeit a rudimentary one due to infants' potentially limited knowledge or linguistics.