25.

polyglots(精通數國語言的人)一看就覺得是很難的詞彙，因此逗號後需做解釋→答案C

The two most common questions asked of linguists are: “How many languages do you speak?” and “How many languages are there in the world?” Both are difficult to answer precisely. Most linguists have varying degrees of familiarity with several languages, and many are polyglots, (C) persons who speak and understand several languages. Charles V, the Holy Roman Emperor from 1500 to 1558 was a polyglot, for he proclaimed: “I speak Spanish to God, Italian to women, French to men, and German to my horse.” As to the second question, it’s hard to ascertain the number of languages in the world because of disagreement as to what comprises a language (A) as opposed to a dialect. A difficulty with both these questions is that the answers rely on a sliding scale. (B) familiarity with a language is not an all-or-nothing affair, so how much of a language do you have to know before you can be said to “speak and understand” that language? And how different must two dialects be (D) before they become separate languages? One criterion is that of mutual intelligibility.