Intelligibility at a multilingual cocktail party: effect of concurrent language knowledge

Our research aims at exploring the nature of the interferences that occur during the speech-in-speech situation. French target words were inserted in 2 types of backgrounds: (i) 4-talker babble spoken in various languages such as French, Italian or Irish, containing acoustic and linguistic information, (ii) fluctuating noise derived from each 4-talker babble signal, with only acoustic information. In Experiment 1, French native participants with no knowledge of Italian or Irish performed a lexical decision task. The comparison of performances obtained with the 2 types of backgrounds for each language revealed that acoustic and linguistic information from babble spoken in a known language to the participants (French) competed with the target words; whereas for babble produced in unknown languages (Italian and Irish) only acoustic information was involved. In Experiment 2, the experimental conditions were identical as in Experiment 1, except that French native participants speaking Italian as L2 and with no knowledge of Irish were recruited. The fact that Italian became an intelligible language to the participants led to acoustic and linguistic interferences from Italian babble.