Youth is not a time of life; it is a state of mind.
青春不是年华，而是心境；

It is not a matter of rosy cheeks, red lips and supple knees.
青春不是桃面、丹唇、柔膝，

It is a matter of the will, a quality of the imagination, vigor of the emotions;
而是深沉的意志、宏伟的想象、炽热的感情；

It is the freshness of the deep spring of life.
青春是生命的深泉在涌流。

Youth means a temperamental predominance of courage over timidity,
青春气贯长虹，勇锐盖过怯弱，

of the appetite for adventure over the love of ease.
进去压倒苟安，如此锐气，

This often exits in a man of 60, more than a boy of 20.
二十后生有之，六旬男子则更多见。

nobody grows merely by the number of years;we grow old by deserting our ideas.
年年有加，并非垂老；理想丢弃，方堕暮年。

Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.
岁月悠悠，衰微只及肌肤；热忱抛却，颓唐必至灵魂。

Worry, fear, self-distrust1 bows the heart and turns the spirit back to dust.
烦忧、惶恐、丧失自信，定使心灵扭曲，意气如灰。

Whether 60 or 16, there is in every human being's heart the lure of wonders,
无论年届花甲，抑或二八芳龄，心中皆有生命之欢乐，奇迹之诱惑，

the unfailing childlike appetite of what's next and the joy of the game of living.
孩童般天真久盛不衰。

In the center of your heart and my heart there is a wireless station;
人人心中皆有一台天线，

so long as it receives messages of beauty, hope, cheer, courage and power from men and from infinite,
只要你从天上人间接受美好、希望、欢乐、勇气和力量的信号，

so long as you are young.
你就青春永驻，风华常存。

When the aerials are down, and your spirit is covered with the snows of cynicism and the ice of pessimism,
一旦天线倒塌，锐气被冰雪覆盖，玩世不恭、自暴自弃油然而生，

then you've grown old, even at 20, but as long as your aerials are up,
几十年方二十，实已垂老矣；

to catch waves of optimism, there's hope you may die young at 80. 
然则只要竖起天线，捕捉乐观的信号，你就有望在八十高龄告别尘寰时仍觉得年轻。

以上为直译版，下面为意译版：

　　青春不是年华，而是心境；青春不是桃面，丹唇，柔膝，而是深沉的意志，恢宏的想象，炽热的感情；青春是生命的源泉在不息的涌流。

　　青春气贯长虹，勇锐盖过怯懦，进取压倒苟安。如此锐气，弱冠后生有之，耳顺之年，则亦多见，年岁有加，并非垂老；理想丢弃，方堕暮年。

　　岁月悠悠，衰微只及肌肤，热忱抛却，颓唐必至灵魂。忧烦，惶恐，丧失自信，定使心灵扭曲，意气如灰。

　　无论年届古稀，抑或二八芳龄，心中皆有生命之欢乐，奇迹之诱惑，孩童般天真久盛不衰。人人心中皆深植一片追求，只要你从天上，人间追求美好，希望，欢乐，勇气和力量，你就青春永驻，风华长存。

　　一旦追求消失，锐气如同冰雪覆盖，玩世不恭，自暴自弃油然而生，即使年方二十，实已老矣。然坚持追求，你就有望在百岁高龄告别尘寰时仍觉年青。