Recent studies in interaction and grammar have demonstrated the importance of examining conversation turn structure for understanding features of grammar. Turn beginnings and endings are seen as particularly important loci for investigation (Schegloff 1996). This study examines two corpora of spoken English to investigate the grammar of turn beginnings in English. A turn initiator is broadly defined as the very first form with which a speaker starts a new turn in conversation. It is found that turn-initial elements in English are overwhelmingly lexical in nature, a result confirming Schegloff’s (1996) hypothesis. Moreover, the data shows that not only are these turn initiators lexical, they also tend to be syntactically independent. It is thus suggested that one of the designing features of the grammar of turns in English involves a short free form of some sort, and English can be considered a turn-initial language in grammaticalizing turn signals. Conversational interactive functions of turn initiators are considered and subcategories suggested. This study also demonstrates some of the advantages of taking a corpus-based approach to language use and looking at turn structure, as exemplified in characterizing the use of some common discourse particles (‘and’, ‘yeah’ and ‘yes’, and ‘this’ and ‘that’).