The relationship between L1 and L2 reading has been investigated drawing on two hypotheses.
First, the linguistic interdependence hypothesis, which claims that L1 reading ability transfers to
L2 reading, i.e., there is always a relationship, hypothetically a correlational one, between L1 and
L2 reading. And second, the linguistic threshold hypothesis, which claims that L1 reading
ability transfers to L2 reading when learners' L2 proficiency is higher than the linguistic
threshold, i.e., some basic linguistic ability is a prerequisite for the transfer to happen.
Researchers, in general, have attempted to find out which hypothesis better explains the
relationship between reading in one language and in another.