Speech act is a technical term in linguistics and the philosophy of language. The contemporary use of the term goes back to John L. Austin's doctrine of locutionary, illocutionary and perlocutionary acts. Many scholars identify 'speech acts' with illocutionary acts, rather than locutionary or perlocutionary acts. As with the notion of illocutionary acts, there are different opinions on the nature of speech acts. The extension of speech acts is commonly taken to include such acts as promising, ordering, greeting, warning, inviting someone and congratulating.