Time Series

Abstract

The time‐series design (TSD) allows applied linguists to investigate two issues: (a) the nature of language use or acquisition over time; and (b) the effect of a specific variable or session of learning on that use or acquisition. The time period of investigation could be seconds and milliseconds, as in applied phonetics research that measures vocal‐fold vibrations (e.g., Mergell, Herzel, & Titze, 2000) and spoken discourse research that measures stages in speech planning and production (e.g., Roberts & Kirsner, 2000). This entry focuses on the study of language use and development across days and weeks and in response to particular sessions of instruction.

Experimental and quasi-experimental designs

“…A time-series design is an example of longitudinal design in which researchers collect samples of language on a regular basis over a set period (Kirk, 2009;Mellow, Reeder, & Foster, 1996). By collecting data on multiple occasions, time-series designs can allow insight into the time course of language development, including changes that may be immediate, gradual, delayed, incubated, or residual (Mellow et al, 1996;Mellow, 2012) as well as the permanency of any effects resulting from a treatment. A time series design is characterized by multiple observations both before and after the treatment.…”