Lower order processes refer to the level of letter and word recognition. Higher order processes refer to the comprehension of the content of text. Efficient word recognition processes are necessary but not sufficient for the successful execution of reading tasks. It allows the reader to allocate optimal attention to the interpretation of meanings communicated in the text but are not sufficient because text comprehension comprises other components as well (e.g. general knowledge).

It is possible that reading comprehension in the second language (i.e. L2) is the application of higher order reading strategies of the first language on the second language. It is also possible that linguistic knowledge of the second language is important for a satisfactory level of text comprehension. Next, it is also possible that the efficient or automized processing of linguistic information is important for successful reading comprehension in the second language. This would thus mean that efficient lower order processing is important for attaining a level of reading skill in the second language with that already attained in the first language. However, it is not clear whether and how reading skills are transferred from the first to the second language.

Metacognitive skills in reading refer to the ability to use strategies to regulate the reading process. These skills are believed to be learned in the first language and transferred to second language reading. It is not clear whether first and second language reading depends on the same skills. The threshold hypothesis states that a threshold level need to be passed before second language readers can apply strategies for text comprehension (e.g. knowledge of vocabulary and grammar). There is no conclusive evidence for this hypothesis.

The speed of lower order processing (i.e. automaticity) may be important for second language reading. This would mean that more than linguistic knowledge is needed for the development of automatic word recognition. When lower order reading processes are inefficient, they will occupy working memory capacity which inhibits controlled, meaning-oriented processes. When it is automatic, working memory capacity can be fully devoted to text comprehension.

Reading comprehension in the first language is predictive of reading comprehension in the second language. It seems as if word recognition speed of the second language does not contribute to second language reading comprehension, though this result is correlational. Both first and second language reading comprehension are explained by combined skill components. However, for the first language only metacognitive knowledge is important whereas vocabulary knowledge and metacognitive knowledge is important for reading comprehension in the second language. Speed components do not contribute significantly to the reading comprehension of either language (i.e. processing speed). It seems as if higher order processing speed is important for reading comprehension of the first language. Processing efficiency on word and syntactic level are important for language two text comprehension. Word recognition speed is not an important factor for normal first language readers.