Why can only some of the Pokémon speak English

Question

I recently saw the 1998 film Pokémon: The First Movie (I can't recommend it), which from my understanding is a direct tie-in to the show. What I don't understand about this film is that all of the Pokémon can only talk using their name... except for two. Mewtwo can talk, and so can this cat-like Pokémon whose name alludes me (he works with Team Rocket). Oddly enough the cat-like Pokémon’s clone cannot speak but I assume that because it was just 'born' it just hasn't learned how yet. I assume that Mewtwo's ability to speak is because the engineers made him that way since Mew can't speak, but I still don't know about the other one.

Is there an explanation for this?

Answer 1

All Pokémon seem to be able to understand human speech, but simply don't know how to replicate it. Apparently, Pokémon can learn to do it through hard work. Bulbapedia recounts the events of Go West Young Meowth:

One day, Meowth came across a female Meowth named Meowzie. She rejected him, saying that he was poor and that she preferred humans, so Meowth attempted to make himself more human-like to make her love him. Thus, he painstakingly taught himself to speak human language and walk upright like a human. When he approached her after this transformation, she once again rejected him, calling him a freak.

So the answer is that it takes time and effort for them to learn to speak, and most don't bother for whatever reason.

Answer 2

Others have mentioned Meowth's ability to speak being something he trained himself to do (with references to the episode which describes it). The other pokemon who have been shown to 'speak' tend to fall into two categories: Legendary pokemon and Psychic pokemon. Some of them, notably Mewtwo, are both.

Initially, Mewtwo was the only non-Meowth Pokemon who could speak, and it was implied that it was possible only because of his incredibly potent psychic abilities and his long exposure to humans. Notably, his 'speech' is also generally shown as telepathy, not verbal speech.

In later movies, notably Kyurem vs. The Sword of Justice, many other Pokemon are able to make themselves understood. That said, most of the time we hear them speak it is to one another. This is not unusual - we see even in the early episodes of the anime that all pokemon understand each other, even if their vocalizations are seemingly simple repetitions of their names. We do, however, see evidence that Kaldeo and Kyurem can make themselves understood by Ash.

It seems that Legendary Pokemon are capable to making themselves understood by humans, but not all Legendaries we have seen use this capability. It's impossible to tell if those we do not see speaking are incapable or simply unwilling.

It seems likely that all Pokemon in the anime could be capable of human speech, but the vast majority are unable or unwilling to put in the time and effort to do so. Legendary pokemon, on the other hand, seem to either be able to communicate with humans innately or at a minimum have a much easier time learning how to do so.

Answer 3

Meowth is a special case, and there is an episode of the anime (Go West, Young Meowth) focusing on this - he spent a lot of time and effort learning to talk human and to walk on his hind legs like a human, in the (mistaken) belief this would cause the female Meowth he loved to love him back. In return for his sacrifice, we find that he can never learn any more Pokémon moves. Meowth sometimes acts as a translator for other Pokémon, and in the episode Island of the Giant Pokémon!? the Pokémon speech is subtitled, showing that Pokémon have their own language which they can speak to other Pokémon with, it's just that no human seems capable of learning it.

Mewtwo too is a special case, being a unique Pokémon created as a more powerful clone of the mythical Mew. He grew up in close contact with a cloned human, Ambertwo, who taught him that the "strange sounds" he was hearing from the scientists were words. Mewtwo, Ambertwo, Bulbasaurtwo, Charmandertwo and Squirtletwo were able to communicate telepathically whilst they were developing and it's possible Mewtwo learnt how to speak to humans from Ambertwo in this way (though Ambertwo was surprised that Mewtwo could communicate with her from the moment he first awoke, so it could also be due to his innate intelligence, telepathic abilities or ancestry). I believe Mewtwo's origin is sometimes cut from Pokémon the First Movie: https://www.dailymotion.com/video/x3v1i97