Here's what we know:
* Natural Language Acquisition: The Creature is highly intelligent and observes the world around him. He learns to read and understand language by observing the De Lacey family, particularly the blind father. This suggests he could potentially understand spoken language as well.
* No Explicit Instruction: The novel doesn't depict the Creature being taught to speak. It's assumed he learns through observation and his own innate abilities.
* Limited Social Interaction: The Creature's lack of interaction with humans, except for brief encounters, would make learning spoken language difficult. He doesn't have a teacher or anyone to practice with.
However, there are some interpretations that suggest the Creature's ability to speak:
* Implicit Abilities: Some readers assume that the Creature can speak based on his ability to understand and communicate in writing, which implies he could also speak.
* Dramatic License: The novel is written in the 19th century, and the portrayal of the Creature's abilities might have been influenced by the limitations of storytelling at that time.
In conclusion, the Creature's ability to speak is not explicitly stated in the novel, but it's implied through his understanding of language and his potential for communication. The exact details of his language development remain a mystery.