Although there are many studies devoted to the problem of Chinese final modal particles, their conclusions usually are not verified by appealing to the opinion of Chinese native speakers. The current study uses the procedure of a semantic experiment and statistical data processing method to analyze key functions of the final modal particle 啊. Respondents were given the fragments selected from Chinese dialogical texts, all these fragments included sentences with the particle 啊 (declarative, imperative, usual interrogative sentences and rhetorical questions). They were asked to evaluate the possibility of excluding the particle from the sentence in the given context without changing the basic meaning of the sentence. If respondents considered such exclusion possible, they also had to explain the difference between the sentences with and without the particle. The analysis of the semantic experiment results identified the following functions of the final modal particle 啊 in a Chinese sentence: 1) softening of the intonation and deescalation of the situation; 2) creation of the communicative tone that is more natural and appropriate to the communicative situation; 3) emphasis of the speaker’s feelings and emotions. These functions have been observed in declarative sentences, imperative sentences and rhetorical questions. In usual interrogative sentences the particle does not have a big influence on a sentence’s meaning that can be explained by the process of its grammaticalization. The function of feeling and emotion’s emphasis indicated by respondents confirms the idea that modus constructions might be the source of Chinese final modal particles.