in a study about Exploring the Components of Language Familiarity and Similarity in Irrelevant Speech,.

The objective of the study was to test whether there was an effect of familiar and unfamiliar languages as well as white noise on immediate free recall. As hypothesized, the results showed that both familiar language(English) and unfamiliar language (Thai) were more disrupted than white noise(no sound) .White noise was a little disrupted though. However, there was no significant difference between English and Thai on thelevel of interference from irrelevant speech effect on immediate free recall.

What would be the role of the brain to understand the cognitive mechanism underlying the irrelevant speech effect in that process where there was no significant difference between familiar language(English) and unfamiliar language ( Thai )on thelevel of interference from irrelevant speech effect on immediate free recall?