Even in the Best-Case Scenario L2 Learners Have Persistent Difficulty Perceiving and Utilizing Tones in Mandarin

Abstract

Lexical tones are widely believed to be a formidable learning challenge for adult speakers of nontonal languages. While difficulties—as well as rapid improvements—are well documented for beginning second language (L2) learners, research with more advanced learners is needed to understand how tone perception difficulties impact word recognition once learners have a substantial vocabulary. The present study narrows in on difficulties suggested in previous work, which found a dissociation in advanced L2 learners between highly accurate tone identification and largely inaccurate lexical decision for tone words. We investigate a “best-case scenario” for advanced L2 tone word processing by testing performance in nearly ideal listening conditions—with words spoken clearly and in isolation. Under such conditions, do learners still have difficulty in lexical decision for tone words? If so, is it driven by the quality of lexical representations or by L2 processing routines? Advanced L2 and native Chinese listeners made lexical decisions while an electroencephalogram was recorded. Nonwords had a first syllable with either a vowel or tone that differed from that of a common disyllabic word. As a group, L2 learners performed less accurately when tones were manipulated than when vowels were manipulated. Subsequent analyses showed that this was the case even in the subset of items for which learners showed correct and confident tone identification in an offline written vocabulary test. Event-related potential results indicated N400 effects for both nonword conditions in L1, but only vowel N400 effects in L2, with tone responses intermediate between those of real words and vowel nonwords. These results are evidence of the persistent difficulty most L2 learners have in using tones for online word recognition, and indicate it is driven by a confluence of factors related to both L2 lexical representations and processing routines. We suggest that this tone nonword difficulty has real-world implications for learners: It may result in many toneless word representations in their mental lexicons, and is likely to affect the efficiency with which they can learn new tone words.

Advanced Second Language Learners of Mandarin Show Persistent Deficits for Lexical Tone Encoding in Picture-to-Word Form Matching

“…Taken together, the excellent tone identification paired with chance performance for tone nonwords suggested to us that auditory tone perception is unlikely to be the primary source of L2 tone word recognition difficulty. A follow-up study used more clearly produced (non)words and once again found a strong difference between tone and vowel nonwords (Pelzl et al, 2020).…”

“…Finally, an L2 listener may have difficulty with phonolexical representations, that is, encoding the lexical units of speech in their mental lexicon. This difficulty may lead to a variety of issues for tone representations: they may be entirely missing, incorrect, only known with some degree of uncertainty, or even confidently incorrect (Pelzl et al, 2020). If a given representation is not faithful to the actual form of the spoken tone word, this has the potential to lead to a variety of problems during lexical access.…”

“…People who grow up speaking a language without lexical tones typically find it difficult to master tonal languages after childhood. They may confuse or misidentify tones in speech early on (e.g., Wang et al, 1999), and they often end up with a large store of fuzzy second language (L2) tone word representations, that is, mental lexical representations with missing, incorrect, or uncertain tone representations (Pelzl et al, 2020). This outcome is not surprising, given that F0 (pitch) is used for many things in non-tonal languages (stress, intonation, emphasis, singing), but does not differentiate one word from another.…”

“…Given that tone identification is already a challenge, it is not surprising that using tones to differentiate words in Mandarin is also difficult for many novice learners (Wong and Perrachione, 2007;Chandrasekaran et al, 2010;Chang and Bowles, 2015). Perhaps less expected is that the same difficulties appear to persist into more advanced stages of learning, even for many learners who have achieved strong categorization or identification abilities (Han and Tsukada, 2020;Ling and Grüter, 2020;Pelzl et al, 2019;Pelzl et al, 2020). We will refer to this type of difficulty as an L2 tone word difficulty, that is, it is not necessarily about tones alone, but about how representations of the tone categories are bound to the lexical representations in long-term memory.…”

“…They will vary from low to high quality, and this is likely to be closely related to a learner's familiarity with those words (Diependaele et al, 2013;Gor and Cook, 2020). An individual word's representation may have tones that are uncertain, incorrect, or completely missing (Pelzl et al, 2020). Each of these problems has the potential to impede fluent spoken word recognition.…”