This study presents a formal generative model that integrates perception and reading, and uses English intervocalic consonants borrowed into Italian as either singletons or geminates to illustrate how the model works. Consisting of words borrowed in the 20th century, our data show that the quantity of the intervocalic consonant in an Italian loanword depends on its written representation in English, the source language. Thus only English intervocalic consonants that are written with two identical letters (for example, as in splatter) are borrowed as geminates. We provide a formalization of these orthographic adaptations with grapheme-to-phoneme mappings in the shape of Optimality-theoretic constraints that model the native reading process, and show how the output of these mappings is restricted by native phonotactic constraints. Furthermore, we illustrate that the native reading grammar proposed here complements the perceptual adaptation model by Boersma and Hamann (2009). This combined model is shown to be able to account for simultaneous orthographic and perceptual borrowings in Italian, as well as to hold for reading and perception outside the realm of loanword adaptation.