Answer:
Based on the reading, the best next sentence would be "He has continued to learn many other languages such as Spanish, Hindi, Croatian, German, and there is no stopping him!"
Step-by-step explanation:
The excerpt talks about Timothy Doner and his ability to learn languages very quickly, then the sentence "He has continued to learn many other languages such as Spanish, Hindi, Croatian, German, and there is no stopping him!" finishes the idea about his successful path on learning, since other languages are mentioned in the previous paragraphs.