If animals suddenly gained the ability to talk, their ability to communicate through speech would likely be visible to humans. However, this would depend on how the animals' newfound language manifests.
There are a few scenarios to consider:
Verbal Communication: If animals could talk like humans, producing audible sounds with their mouths, then yes, humans would be able to see them speaking. They would move their mouths and produce sound waves, just as humans do when they speak.
Telepathic Communication: Alternatively, if animals gained the ability to communicate telepathically (mind-to-mind communication), their conversations would not be visible to humans. In this case, the animals' communication would be happening on a mental level, and humans wouldn't be able to physically see or hear the exchange.
Visible Aura or Signals: In a more fantastical scenario, the animals might emit visible signals or auras while communicating, making their interactions observable to humans.
However, regardless of how the communication is manifested, the implications of animals suddenly gaining the ability to talk would be significant. It could lead to a revolution in our understanding of the animal kingdom, ethics regarding animal rights, and our relationship with other species on Earth. It's essential to recognize that such a scenario would be a major paradigm shift and have profound effects on human society.