十九岁少年英文是 "nineteen-year-old teenager"。
其中 "nineteen" 来自英文数字 "19"，"year" 来自英文 "year"，意为 "年"，"old" 来自英文 "old"，意为 "年龄长的"，"teenager" 来自英文 "teenager"，意为 "青少年"。
英文例句及中文翻译：
My older brother is a nineteen-year-old teenager. 我的哥哥是一个十九岁的青少年。
He's still a teenager, but he'll be an adult next year. 他现在还是个青少年，但明年就会成为成年人了。
She's always been mature for her age, even as a teenager. 她一直很成熟，即使在青少年时期也是如此。
其中 "nineteen" 来自英文数字 "19"，"year" 来自英文 "year"，意为 "年"，"old" 来自英文 "old"，意为 "年龄长的"，"teenager" 来自英文 "teenager"，意为 "青少年"。
英文例句及中文翻译：
My older brother is a nineteen-year-old teenager. 我的哥哥是一个十九岁的青少年。
He's still a teenager, but he'll be an adult next year. 他现在还是个青少年，但明年就会成为成年人了。
She's always been mature for her age, even as a teenager. 她一直很成熟，即使在青少年时期也是如此。