Is a shared interlanguage beneficial? Mutual intelligibility of American, Dutch and Mandarin speakers of English

We determined the mutual intelligibility Mandarin Chinese, Dutch and American speakers of English in all nine logically possible combinations of speaker and listener native language backgrounds. Designated speakers (one male, one female per language group) were selected from larger sets of 20 speakers so as to be optimally representative of their peer groups. All non-native speakers and listeners were university students who did not specialize in English and had never lived in an English speaking community. Intelligibility was tested in separate tests targeting vowels, onset consonants, onset consonant clusters, words in syntactically correct but semantically empty sentences (SUS test), and words in meaningful sentences in which they appeared in either low or high predictability contexts. We test the hypotheses that mutual intelligibility between speaker and listener is better as (i) their native languages resemble each other more, and (ii) if speaker and listener share the same native language. In order to test the second hypothesis we propose a new method for quantifying the so-called interlanguage speech intelligibility benefit (ISIB).