Dunstan Baby Language is a theory about infantile vocal reflexes as signals, in humans.
The theory is that across cultures and linguistic groups there are five sounds, each with a meaning, that is used by infants before the language acquisition period. The hypothesis has not yet been scientifically validated however it is still incredibly fascinating.
According to Dunstan, the five universal words (or sound reflexes) used by infants are:
Neh (I'm hungry) – An infant uses the sound reflex "Neh" to communicate its hunger. The sound is produced when the sucking reflex is triggered, and the tongue is pushed up on the roof of the mouth.
Owh (I'm sleepy) – An infant uses the sound reflex "Owh" to communicate that they are tired. The sound is produced much like an audible yawn.
Heh (I'm experiencing discomfort) – An infant uses the sound reflex "Heh" to communicate stress, discomfort, or perhaps that it needs a fresh diaper. The sound is produced by a response to a skin reflex, such as feeling sweat or itchiness in the bum.
Eairh (I have lower gas) – An infant uses the sound reflex "Eairh" to communicate they have flatulence or an upset stomach. The sound is produced when trapped air from a belch is unable to release and travels to the stomach where the muscles of the intestines tighten to force the air bubble out. Often, this sound will indicate that a bowel movement is in progress, and the infant will bend its knees, bringing the legs toward the torso. This leg movement assists in the ongoing process.
Eh (I need to be burped) – An infant uses the sound reflex "Eh" to communicate that it needs to be burped. The sound is produced when a large bubble of trapped air is caught in the chest, and the reflex is trying to release this out of the mouth.