This study examined classroom routine and interactional patterns of Grade 5 English Language reading comprehension lessons through delineating the speech act functions of instructional discourse that was based on Malcolm's sociolinguistic model (Malcolm, 1979a; Malcolm, 1979b; Malcolm, 1982; Malcolm, 1986). It also evaluated the classroom interaction patterns with reference to four proposed levels of vocabulary learning opportunities that could be afforded through the discourse. Using a qualitative single case study methodology, four video-recorded and transcribed lessons, together with a semi-structured interview with the teacher, classroom observations, and lesson plans formed the data for the present study. The classroom routine showed teacher's informing, teacher's elicitation, children's bidding, teacher's nomination, children's replying, teacher's acknowledgement, teacher's informing and teacher's directing and a predominant Initiation-Response-Follow-up pattern. The teacher's discourse had focussed the learners' attention on target vocabulary and was effective in eliciting the meanings of those words from the learners. However, most of the successful elicitations took few and short turns. A closer examination further revealed that the most prevalent teacher's elicitation acts were checking elicitation and multiple elicitation; and that the most prevalent teacher's acknowledgement acts were unqualified accepting or relaying, and evaluating. The types of teacher's elicitations and acknowledgements resulted in an interaction that was devoid of dynamic negotiation of the meanings between the learners, teacher, and text.