Kilma & Bellugi (1966)

• Kilma and Bellugi explored the stages of interrogative acquisition.
• Kilma and Bellugi found a questioning function is initially expressed prosodically with rising intonation, before an interrogative pronoun is realised at the beginning of the utterance.
• Kilma and Bellugi found children were able to structure closed interrogatives with an initial auxiliary element before they could employ initial interrogative pronouns with standard syntactic structure.