SAFMEDS (Say All Fast Minute Every Day Shuffled) cards, in conjunction with graphing learner’s progress, were used as an intervention to teach Welsh vocabulary to second language learners in four year-7 classes (12-year-olds) in an English medium secondary school in Wales. A further class of children of the same age served as a Waiting List Control (WLC). From the curriculum, 200 words were selected by teachers to be studied during the school term. Children in all classes were given a pre-test to establish the number of words that each child already knew at baseline. Children in the four intervention classes were each given packs of Welsh-English SAFMEDS and required to pair up with another child. Both children were instructed to conduct a practice run followed by a 1-minute timing at the start of each 50-minute lesson (3 lessons per week). Children then recorded their correct and incorrect responses on data sheets and graphs. The procedure took less than 5 minutes, and the teacher then continued with the scheduled lesson. The WLC class received their normal Welsh classes. The intervention spanned four weeks of the term and was followed with a post-test of the target words for all children. During the post-test, the intervention children wrote significantly more correct Welsh vocabulary words than the control children, p < .001, d = 1.54. The study demonstrates that SAFMEDS are an efficient and effective method to enhance vocabulary learning with brief exposure within the context of standard lessons.