The phrase is constructed very logically. 说话 (shuōhuà) means “to speak” or “the words that were spoken.” 不算数 (bùsuàn shù) literally means “doesn't count as a number,” which idiomatically translates to “doesn't count,” “is not valid,” or “doesn't hold.” Together, 说话不算数 (shuōhuà bùsuàn shù) means “what was said doesn't count”—a straightforward way to say a promise has been broken.
In Chinese culture, a person's word is deeply connected to their honor, integrity, and social standing. The concept of 信 (xìn) - which translates to trust, credibility, and faithfulness - is a cornerstone of Confucian values. To be a trustworthy person (守信用 - shǒu xìnyòng) is a highly respected trait. Therefore, being accused of 说话不算数 is not just a casual complaint; it's a serious critique of one's character. It implies a lack of integrity and can significantly damage one's 面子 (miànzi), or “face.” A useful Western parallel is the phrase “actions speak louder than words.” However, there's a key difference. The Western phrase emphasizes that actions are *more important* than words. 说话不算数 focuses on the failure of the words themselves—the promise was made, and the words proved to be empty. In many social and even business contexts in China, a verbal commitment is taken very seriously, summed up by the idiom 一诺千金 (yí nuò qiān jīn) — “one promise is worth a thousand pieces of gold.” To go back on that promise is a major social transgression.
This phrase is extremely common in everyday life. Its severity depends heavily on the tone and context.