The process of pronunciation is accompanied by energy planning and consumption. Energy in a broad sense is a ‘resource’. Many phonetic phenomena are related to the quantity of the ‘resource’. For example, stress is often considered to occupy a larger amount of ‘resource’, which is why it appears particularly prominent. But what parameters are used to describe the quantity of pronunciation? This is a question worth studying. This article starts with the issue of stress, studies various acoustic factors that affect stress perception, and then finds an effective parameter that reflects the quantity of pronunciation - Times of vibration of vocal folds (TVVF). Previous studies in phonetics have suggested that pitch and duration are important acoustic parameters that affect stress perception. However, for tonal languages like Mandarin, these two parameters may not be the best parameters for representing stress. Because different tones have different pitch and duration characteristics, these parameters cannot reflect the stress levels well. This study found that TVVF better reflects stress levels than pitch and duration. TVVF represents the times of vibration of vocal folds during pronunciation and the number of pulses of a syllable in acoustics. Since the number of pulses is the integral of pitch and duration, TVVF is a fusion parameter of pitch and duration. Research has shown that TVVF is a more effective parameter for indicating tonal language stress level than other acoustic parameters. In addition, TVVF can effectively reflect the quantity pattern of pronunciation in large prosodic units. We found that the number of syllables in a big prosodic unit is inversely related to the average TVVF of syllables. That is to say, there is a conservation phenomenon in the TVVF of prosodic units. We refer to it as the principle of ‘Quantitative conservation of pronunciation’. In summary, TVVF is an effective quantitative parameter for describing pronunciation and can be used in various quantity-related studies.