Dézhī zhòngjiǎng de xiāoxi, tā xǐ bú zì shèng, jīdòng de shuō bu chū huà.
Hearing the news that she had won the prize, she was so overjoyed she couldn't speak.
Tips
history
First attested in the Yuan dynasty play 《西厢记》 (Xīxiāngjì, Romance of the Western Chamber) by 王实甫 (Wáng Shífǔ): 承夫人亲自饯行，喜不自胜 ('that the lady should send him off in person — he could not contain his joy'). The phrase has been a stock literary expression of overflowing delight ever since.
memory
Key character is 胜 (shèng) here meaning 'to bear / to withstand' — not 'to win.' So 不自胜 = 'cannot bear oneself,' i.e., the joy is too much to handle. Same usage in 不胜感激 (bú shèng gǎnjī, immeasurably grateful).
