In the present study, we examine sentence reading in low-proficiency Spanish learners using an eye-tracking methodology. This method reveals the real-time, uninterrupted process of reading comprehension, and can therefore shed light on L2 learners' functional proficiency. We created sentence pairs that were identical except for one word. The contrasting words in the sentence pairs differed in processing difficulty; in this case, the more difficult word had a lower frequency of occurrence. The effect of frequency on reading typically manifests as longer reading times, particularly when readers first encounter the critical word. The relative difficulty created by a low-frequency word is usually localized to the word itself. Results show a significant difficulty effect for both the learner group and control group. However, they also show that although the effect was localized in the control group, it was not localized in the learners: difficulty "spilled over" into the subsequent region, suggesting that these readers read at too fast a pace, which could lead to extensive re-reading. We believe that this pattern of reading could be remediated and suggest ways for doing so.