Select the option that can be used as a one-word substitute for the given group of words.
Someone who speaks more than one language

The correct answer is Polyglot.

Let's break down the meaning of the given phrase and the provided options to understand why:

1. Given group of words: "Someone who speaks more than one language"
2. Polyglot: This term is derived from the Greek words poly (meaning many) and glotta (meaning tongue or language). Therefore, a polyglot is literally someone who is able to speak, write, or understand many languages. This perfectly matches the given description.

Let's look at the other options to understand why they are incorrect:
- Heretic: A person holding an opinion or belief at odds with what is generally accepted, especially in religion.
- Fatalist: A person who believes that all events are predetermined and therefore inevitable.
- Insolvent: A person or organization that is unable to pay their debts.