Polish is a language where true geminates appear and the occurrence of a double consonant letter in spelling corresponds with double or at least prolonged consonant articulation regardless of the morphological structure of the word. The above principle also concerns most borrowings, such as the English word ‘hobby’, for instance. In English, true geminates do not occur and a morpheme-internal double consonant letter is only a fairly reliable indication of the way the preceding vowel should be pronounced. This discrepancy may lead to negative transfer in Polish learners of English. Our recent research of native Polish speech (Rojczyk and Porzuczek, in press) generally confirmed the results reported by Ladefoged and Maddieson (1996), among others, who found geminates to be 1.5-3 times longer than singletons. In our study we investigate the influence of double consonant letters on L1 and English pronunciation of Polish learners. They read trochaic family names containing intervocalic <nn>. Each name is preceded by a first name suggesting the nationality (Polish, English, German or Italian) of the person mentioned. By placing each tested item in a Polish and an English semantically and rhythmically equivalent sentences (This is .../To jest...), we measure the level of consonant length variation with respect to the language in which the potential geminates appear, the language context and the learning experience of the students. In this way we collect evidence and formulate observations concerning the learners’ awareness of the status of geminates in various languages and the probability of transfer in EFL learning.