Sentence 3 is an outlier, deviating from the primary subject of the other sentences. The remaining sentences examine the naming conventions of numbers in English, emphasizing inconsistencies and variations. In contrast, sentence 3 focuses on children's learning process and their understanding of number distinctions, such as between "fourteen" and "forty." The other sentences collectively discuss the intricacies of English number nomenclature, making sentence 3 somewhat tangential to the paragraph's central theme.
Therefore, the accurate choice is (C): It can take children a while to learn all these words, and understand that "fourteen" is different from "forty".