The paper shows how British English centering diphthongs are adapted to the vowel space of Polish learners of English. The goal is to focus on complex vowels and the interaction of qualitative and quantitative features. Acoustic analysis revealed various processes used to overcome pronunciation difficulties: /j/ and /w/ breaking, /r/ insertion, substitutions of other vocalic qualities, changes in diphthong duration and diphthong phases duration, and changes in the rate of frequency change
