However, other studies contest that the evidence for the CPH is not as exact as thought and suggest that, for example, the number of years that one studies an L2 is more influential on final acquisition (Strid, 2017;Birdsong and Molis, 2001;Marinova-Todd, 2003;etc.).
the CPH is a controversial theory in SLA, with many researchers claiming that earlier exposure to an L2 (i.e.