I reread chapter 1 and got confused. Ash saw mew and mewtwo etc. less than 999 years ago-alot less. So how can mew etc. be alive??
Therefore, Mark gets what Eevee is saying from the context and his bodily expressions (which are a big part of the language of Pokémon), not a word for word meaning that can be translated. Sandshrew hasn't been very talkative, but when he's said something, it's always been obvious what he was saying so I didn't feel the need to actually translate it (such as '“Sand,” said the Pokémon, nodding', where the context easily tells you that he's agreeing to what Mark was saying in some way or another). You're going to see real conversations with Eevee and Sandshrew later, and then they will be translated.Chapter 6 said:“Vee?” the Pokémon questioned. Not having very good control of Pokémon’s complicated language due to young age, he managed to get his meaning across, but not word for word.