Charlie's transport was a ship that suffered a crash landing on the planet Thasus circa 2252. Charles Evans was the lone survivor. It was equipped with microtapes and enough food concentrates to last approximately a year, according to Spock.
When Doctor Leonard McCoy expressed doubt in 2266 that the ship's food supplies would have lasted fourteen years, Charlie claimed to have found food "growing around" on the planet`s surface after the ship's supply was exhausted, and that he learned to talk by listening and responding to the ship's memory banks. (TOS: "Charlie X")