<![CDATA[Pronunciation remains one of the most persistent challenges faced by English as a Foreign Language (EFL) learners in Indonesia, particularly at the segmental level, where the phonological system of Indonesian differs substantially from that of English. This study employed a qualitative case study design to investigate the segmental pronunciation difficulties of EFL undergraduate students enrolled in a Pronunciation course at an Indonesian university. Data were collected through an audio-recorded Word List Reading task consisting of 25 target words distributed across three phonetic groups - consonant errors, vowel confusion and diphthong reduction, and final consonant deletion - and analyzed using International Phonetic Alphabet (IPA) transcription together with a standardized error-coding system (C-sub, V-conf, Diph, FC-del). In-depth analysis of two case participants revealed distinct yet overlapping error patterns. The first participant predominantly substituted the interdental fricative /θ/ with /t/ and the labiodental fricative /v/ with /f/, reflecting consonant substitution as the most frequent error type. The second participant produced more frequent vowel confusion, particularly involving the contrasts /æ/-/e/ and /iː/-/ɪ/, as well as diphthong substitution. Both participants exhibited final consonant deletion in words containing coda consonants and consonant clusters. These findings are interpreted as evidence of first language (L1) phonological interference, consistent with the Contrastive Analysis Hypothesis and Flege's Speech Learning Model. The study concludes that segmental pronunciation instruction for Indonesian EFL learners should explicitly target the consonant and vowel contrasts that are absent from the Indonesian sound system.]]>
