The aim of the paper was to document further the case of VA who possesses colored speech sound synesthesia. To do so, different stimuli were presented to VA: isolated vowels, nonsense syllables, and words. VA systematically perceived a color for each phoneme and we observed that only the articulatory and acoustic factors linked with changes in phonemic category influenced the colors perceived. Semi-structured interviews indicated that in the context of conversation, VA had to translate color into phonemes into her constructed linguistic representations which has a cognitive cost. She also reported having a visual cognitive style in which the verbal dimension is almost non-existent. This is the first time that genuine phoneme color synesthesia has been described. In the discussion, we address several implications of this synesthesia: the cognitive cost of this stable system, the atypical speech perception that it implies, and its relation to a specific cognitive functioning.