Research on foreign language speech production often focuses on repeated speech and read speech. To the best of our knowledge, only a few studies have investigated the role of the complexity of speech production tasks on the abilities to produce sounds in a foreign language. The present study aims to fill this gap. We recorded adult French native speakers with German as a second language (L2). The participants performed three speech tasks: word repetition, reading and picture description. Note that, the picture description task is a semi-spontaneous speech task, which can be considered to be closer to a real life speech experience than the two other tasks. We assume that L2 production complexity depends upon the three tasks and on the linguistic information provided: the sound in the repetition, the text in reading, and no linguistic information in picture description. We created two corpora of German speech: the FLACGS and the ProFee-FLACGS corpora. The speech resources were analysed regarding word initial /h/ and vowel duration contrast production. Taken together, our results show that both increasing L2 speech production complexity as well as conflicting grapheme-phoneme conventions in the two languages have an impact on production accuracy in L2 speech. Moreover, L2 learners tend to achieve native like productions when provided with a native German auditory input. Awareness of pronunciation differences between ones first and second language can help with the amount of correct sound production but it has very limited impact on the accuracy of the produced sounds.