In this single case study with a multiple baseline approach, a five year-old Swedish boy, diagnosed with an autism spectrum condition, and having a bilingual background, was followed weekly for one year. In order to facilitate the acquisition of phonological contrasts and knowledge of symbolic representations, a training package with minimal pairs was gradually introduced. A corpus of the utterances in interaction with teachers and a speech pathologist was collected, transcribed, and analyzed. The results of the study showed a quantitative and qualitative development of sound production involving the use of new phonological feature types, new syllable constructions, and new words during the year. The delayed and deviant speech development, both concerning segments, syllables, and word boundaries in this child, is in line with studies that describe a deviant phonological development in individuals with autism.