Jillian, a flight attendant, is fluent in spanish. ever since she has learnt french, however, jillian finds it difficult to remember spanish words and phrases. in this scenario, jillian's failure to retrieve spanish words and phrases is most likely caused by

Language attrition.

Language attrition, or wearing away of language, usually happens when we immerse in another language and then later on, be surprised to find we have difficulty returning to the language we have already learned.

This plays a crucial role during the initial stages of second language learning.  That is, when first learning a new language, we have to actively ignore our easily accessible first and second language words while struggling to express our thoughts in a novel tongue.

As a speaker achieves bilingual fluency, this inhibition becomes less necessary, accounting for the better performances of fluent bilingual speakers in the study.