(A) As he grew older, John's dedication to learning foreign languages in school and on his own became more apparent, and he continued to expand his knowledge of different tongues and cultures.
(B) Growing up in a household where his parents spoke different languages provided John with a rare opportunity to immerse himself in different linguistic cultures.
(C) Driven by his unwavering commitment to language learning, John went on to become proficient in several languages and pursued a career as a highly-skilled translator.
(D) John's experience with learning foreign languages is unlike any other, as he has had a unique upbringing that allowed him to develop a deep appreciation and fascination for languages.
(E) With his innate talent for language acquisition, John was able to quickly assimilate new vocabulary and grammar rules, and he relished the challenge of mastering complex linguistic concepts.
(F) The exposure to multiple languages at an early age sparked John's interest in language learning and instilled in him a lifelong passion for exploring different dialects and linguistic systems.

Which of the following would be the SECOND sentence after rearrangement?

To determine which sentence comes second after rearrangement, let us analyze the logical flow and chronological connection between the sentences:

1. Sentence (B) serves as the best opening sentence. It introduces John's childhood and the initial context of his upbringing: "Growing up in a household where his parents spoke different languages provided John with a rare opportunity to immerse himself in different linguistic cultures."
2. Sentence (F) directly connects to the idea introduced in (B). The phrase "The exposure to multiple languages at an early age" in (F) refers back to the household environment described in (B). Thus, (F) logically follows (B) as the second sentence: "The exposure to multiple languages at an early age sparked John's interest in language learning and instilled in him a lifelong passion for exploring different dialects and linguistic systems."
3. Sentence (A) continues the chronological progression of John's life (moving from childhood to growing older): "As he grew older, John's dedication to learning foreign languages in school and on his own became more apparent..." (Third sentence).
4. Sentence (E) builds on his academic dedication by describing his talent and acquisition process: "With his innate talent for language acquisition, John was able to quickly assimilate new vocabulary..." (Fourth sentence).
5. Sentence (C) shows the career outcome resulting from his dedication: "Driven by his unwavering commitment to language learning, John went on to become proficient in several languages and pursued a career as a highly-skilled translator." (Fifth sentence).
6. Sentence (D) serves as a concluding summary reflecting on his overall journey: "John's experience with learning foreign languages is unlike any other, as he has had a unique upbringing that allowed him to develop a deep appreciation and fascination for languages." (Sixth sentence).

The correct order of the sentences is B-F-A-E-C-D.

Therefore, the second sentence after rearrangement is F.