Learning to read affects speech perception. For example, the ability of listeners to recognize consistently spelled words faster than inconsistently spelled words is a robust finding called the Orthographic Consistency Effect (OCE). Previous studies located the OCE at the rime level and focused on languages with opaque orthographies. This study investigates whether the OCE also emerges at the phonemic level and is a general phenomenon of languages with alphabetic scripts, including those with transparent writing systems. Thirty French (opaque language) and 30 Spanish (transparent language) listeners participated in an auditory lexical decision task featuring words and pseudowords including either only consistently spelled phonemes or also inconsistently spelled phonemes. Our results revealed an OCE in both French and Spanish which surfaced as longer reaction times in response to inconsistently spelled words and pseudowords. However, when analyzing the data split by language, the OCE was only detectable in French but not in Spanish. Our findings have two theoretical implications. First, they show that auditory lexical processing is impacted by orthographic information that is retrieved at the phonemic level, not just the rime level. Second, they suggest that the OCE may be modulated by a language's opacity. In conclusion, our study highlights the depth of literacy effects on auditory language processing and calls for further investigations involving highly transparent languages.