This article compares two approaches to genre analysis: Biber’s multidimensional analysis (MDA) and Tribble’s use of the keyword function of WordSmith. The comparison is undertaken via a case study of conversation, speech, and academic prose in modern American English. The terms conversation and speech as used in this article correspond to the demographically sampled and context-governed spoken data in the British National Corpus. Conversation represents the type of communication we experience every day whereas speech is produced in situations in which there are few producers and many receivers (e.g., classroom lectures, sermons, and political speeches). Academic prose is a typical formal-written genre that differs markedly from the two spoken genres. The results of the MDA and keyword approaches both on similar genres (conversation vs. speech) and different genres (the two spoken genres vs. academic prose) show that a keyword analysis can capture important genre features revealed by MDA.