This dataset contains tabular files with acoustic measurements for two English vowel categories, TRAP and DRESS, produced by n = 62 German learners of English and n = 26 native speakers of English (BrE and AmE). The German subjects are instructional-setting learners ranging from grade 5 (age: 11) to university. They are predominantly from northern Bavaria and represent a broad range of proficiency levels. Pronunciation ability was assessed with a foreign accent rating. The data were elicited with carrier phrases ("I said ..., not ...") and each subject produced n = 12 monosyllabic words (n = 6 tokens for each vowel category). Measurements are reported for F1, F2, and the duration of the vocalic interval. Formant measurements were normalized using the procedure proposed by Lobanov (1971). See ReadMe file for more details. Related publication: Soenning, Lukas. 2020. Phonological variation in German Learner English. University of Bamberg dissertation. DOI: 10.20378/irb-49135 Open access: https://fis.uni-bamberg.de/handle/uniba/49135