How do basic color terms evolve?

The first appearance of an Eevee in the Pokémon anime was in Episode 40, "The Battling Eevee Brothers". In this episode, Ash's party comes upon a family of four brothers, who all have or have had Eevees. Each of the three older brothers have evolved their Eevees into either a Flareon, a Jolteon, or a Vaporeon, and they are pressuring their youngest brother Mikey to evolve his Eevee, too. What they fail to notice is that he doesn't want to evolve it. However, when Team Rocket steals all of the Pokémon, Mikey proves that his Eevee does not need to evolve as it defeats Team Rocket when his brothers' Pokémon were unable to.