"[...] the results of the 2011 Progress in International Reading Literacy Study (PIRLS) were published. [...] There's a small but decisive factor that is often forgotten in these discussions : differences in orthography across languages. Lots of factors go into learning to read. The most obvious is learning to decode -learning the relationship between letters and (in most languages) sounds. Decode is an apt term. The correspondence of letters and sound is a code that must be cracked.
In some languages the correspondence is relatively straightforward, meaning that a given letter or combination of letters reliably corresponds to a given sound. Such languages are said to have a shallow orthography. Examples include Finnish, Italian, and Spanish.
In other languages, the correspondence is less consistent. English is one such language. [...]"