We used to think that the brain was fully developed by very early teenagerhood and we now realise that the brain doesn’t stop developing until mid-20s or even early 30s. There’s a lot more information and evidence to suggest that actually brain development in various forms goes on throughout the life span.
The first modern coin-operated vending machines were introduced in London in the United Kingdom in the early 1880s, dispensing post cards. The machine was invented by Percival Everitt in 1883 and soon became a widespread feature at railway stations and post offices, dispensing envelopes, postcards and notepaper.
Even the Oxford English Dictionary throws its hands up and admits “of the actual origin we have no evidence.” But, the OED continues, “the forms dada and tata, meaning ‘father,’ originating in infantile or childish speech, occur independently in many languages.” In other words, “dad” might come from baby babble and entered adult vocabulary from there as “dad,” but it’s not a sure thing.