Step 1: Understanding the Question:
The task is to find a single word that means "a person who speaks many languages".
Step 2: Key Formula or Approach:
The approach is to understand the meaning of the given options, particularly by paying attention to their root words or prefixes.
Step 3: Detailed Explanation:
Let's define each option:
(A) Bilingual: A person who speaks two languages fluently. The prefix "bi-" means two.
(B) Polyglot: A person who knows and is able to use several languages. The prefix "poly-" means many. This matches the definition in the question.
(C) Linguist: A person who studies linguistics, the science of language. A linguist might not necessarily speak many languages.
(D) Orator: A skilled and eloquent public speaker. This relates to speaking skill, not the number of languages spoken.
Step 4: Final Answer:
The correct one-word substitution for "a person who speaks many languages" is "Polyglot". Option (B) is the correct choice.