本文從語用學和句法學的角度探討粵語的疑問句末助詞“咩”和“嗬”。透過比較“咩”、“嗬”和普通疑問句之語境，本文指出“咩”和“嗬”同時發揮兩種語力（陳述和發問），是一個複雜的言語行為，與簡單疑問句有別。語義上，“咩”是個以說話者為中心的語氣詞，而“嗬”則以受話者為中心。另一方面，本文分析兩個語氣詞與各種疑問句的並存限制、轄域，及輸入之小句種類，發現句法結構上，一個語氣詞中心語並不足夠，而且“嗬”必須比“咩”高。因此，本文提出由兩個語氣詞中心語構成的“複合語氣詞短語”──“咩”為較低的中心語FORCES(peaker)，而“嗬”則在第二層較高的FORCEA(ddressee)。

This study of syntax-pragmatics interface analyzes the meaning of two Cantonese question particles, namely me1 and ho2, and contrasts their felicity conditions with that of neutral questions. Both particles introduce complex speech acts which exercise two illocutionary forces (asserting and asking), contrary to neutral questions which are simple speech acts. Co-occurrence patterns of question particles, scope facts and clause-typing restrictions suggest that the addressee-oriented particle ho2 is higher than speaker-oriented me1 in syntax. A complex ForceP structure is proposed, in which a higher head FORCEA(ddressee) hosts ho2, while FORCES(peaker) hosts me1.