Possible extensions and limitations to L2 prosodic research

In this subsection, I will proceed the evaluation of the possible extensions and limitations of the presented models and theories to account for the learning of L2 prosodic contrasts.

CAH

The CAH, which was not specifically proposed to account for phonological phenomena, was applied for the research of L2 phonology. According to Ringbom (1994, 738), con-trastive phonology is the area in which the predictions of a concon-trastive analysis work best.

However, it seems that the comparison between L1 and L2 phenomena is not straightfor-ward in all research areas in phonology, such as in prosody. For some of the categories of the hierarchy of difficulties proposed by Stockwell et al. (1965), it is difficult to find a suitable example in the prosodic domain (e.g. for the categories “split” or “coalesced”, see Figure 1.1). For other categories, it is difficult to define what does “completely new”

or “completely absent” mean. For instance, Japanese lexical use of pitch accents for Ger-man learners of Japanese could be claimed to be “completely new”, however, the use of pitch accents itself is not new for German, because they are used not at the lexical level, but at the post-lexical or paralinguistic level. Therefore, it should be clarified what is

“completely new” in this case. For the easiest category (= an L1 and an L2 category com-pletely correspond to each other), an example would be that both German and Japanese apply a rising boundary tone for a polar question. Note that the phonetic realisation of

1.4 Prosodic transfer in the models and theories of L2 acquisition 17 the rising boundary tone in Japanese (Fujisaki and Hirose, 1993) is different than the one in German (Michalsky, 2014), so that it is ultimately not clear, whether this prosodic phe-nomenon “completely correspond” to each other despite the phonetic differences. Some terms used in the predictions (such as “completely correspond” or “correspond new”) are too vague to make predictions on cross-language prosodic transfer.

For all aforementioned five categories, it is more clear to find examples at the seg-mental level e.g. by comparing L1 and L2 vowels and consonants. What the contrastive analysis of L1 and L2 prosody makes more difficult is that the same prosodic property may be layered at different linguistic levels in an L1 and an L2. Moreover, differences can be manifested at the phonological level, but also at the phonetic level. Therefore, mul-tiple aspects of the same prosodic phenomenon in an L1 and an L2 must be taken into account together. For this reason, it is difficult to define what is new or absent between the L1 and L2. The same phonological category (e.g. a rising boundary tone) may have cross-language differences in the phonetic realisation forms. Since there are phonetic variations within a prosodic category, it is crucial to determine whether an instance of an L2 category can be identified as a member of an L1 category. In order to compare prosodic phenomena cross-linguistically, it is important to take different dimensions of prosodic transfer into account.

MDH

The applicability of the MDH to the research on L2 prosodic transfer has two opposite views. Rasier and Hiligsmann (2007) support the MDH to best predict prosodic transfer and applied it in his study on L2 acquisition of pitch accent in Dutch and French. They claimed that structural constraints on accentuation outweigh pragmatic information in French, while it is the opposite in Dutch. Many other languages rely on both structural and pragmatic rules in their accent placement strategies, albeit in a different order of preference. But there seems to be no language where structural constraints are totally absent, see Figure 1.3.

Figure 1.3Typology of accented system Rasier and Hiligsmann (2007, 53)

18 General introduction They thus defined that structural accentuation rules constitute the unmarked case, whereas pragmatic ones the marked case and assumed that the German pragmatic straint for French L2 learners is more difficult to acquire than the French structural con-straint for German L2 learners. Their production experiment approved their assump-tion. On the other hand, He (2012) stated the limitation of the MDH for the research on acquisition of L2 prosody. He argued that the MDH presupposes the concept of linguis-tic universals (Greenberg, 1966) and its scope may be restricted to linguislinguis-tic areas such as syllable structures or the frequency of segmental speech sounds for which linguistic universals have been proposed. Other phonological features and prosodic phenomena are difficult to be classified in terms of typological markedness, so the MDH may not be able to predict their acquisition (He, 2012, 21).

Let’s take an example from a prosodic phenomenon investigated in my thesis; pitch accents in German and Japanese. While German exhibits the post-lexical and paralin-gusitic use of pitch accents, Japanese additionally employs the lexical use of pitch ac-cents. Applying the logic made by Rasier and Hiligsmann (2007), the lexical use of pitch accents supposed to be marked and the post-lexical and paralinguistic use of them un-marked. Following the MDH, the acquisition of Japanese lexical pitch accents by Ger-man L2 learners should not be as difficult as the acquisition of GerGer-man pitch accents by Japanese L2 learners. However, it is questionable whether the acquisition of pitch ac-cents at the lexical level and at the post-lexical level are qualitatively comparable. More-over, even though both languages use pitch accents at the post-lexical and paralinguistic level, it seems that the acquisition of post-lexical and paralinguistic use of pitch accents in Japanese as L2 and German as L2 seems to be qualitatively different, since the post-lexical and paralinguistic use of pitch accents in Japanese are restricted by their post-lexical use (Asano, 2015), whereas pitch accents in German do not have such a lexical restric-tion. These examples indicate the complexity of the notion of markedness. Since my thesis primarily investigates the processing of L2 prosody and does not mainly aim at discovering the hierarchy or grade of difficulties of certain prosodic phenomena in com-parison to other prosodic phenomena, I will merely make use of the notion of comparing L1 and L2 prosodic phenomena to predictpossible(but not all) difficulties in L2 acquisi-tion.

SLM and PAM

SLM: Flege et al. (1995a) explicitly states that the model is proposed to account for the ac-quisition of L2 segments (vowels and consonants) and to make predictions based in the

1.4 Prosodic transfer in the models and theories of L2 acquisition 19 phonetic systems used in the perception and production of vowels and consonants. The four postulates proposed in the SLM present the processes and mechanisms of the ac-quisition of L2 segments rather in general terms, which could be empirically investigated in the research of prosody. Most of the seven hypotheses proposed in the SLM require to empirically measure or to define perceived (dis)similarities, what is often difficult to do for prosodic phenomena. A distance between two vowels in the phonological space and the perceived (dis)similarity between the vowels can be measured by their F1, F2 and F3, thus it is relatively clear to define. Researchers measure a distance between an L1 and L2 consonant by comparing their place and manner of articulation and by examining whether a similar consonant to the L2 consonant exist in the L1. In this way, their per-ceived (dis)similarities are quantifiable. However, in the case of prosodic contrasts such as ours, it is difficult to define the perceived (dis)similarities. For instance, how can a per-ceived (dis)similarity between a Japanese lexical pitch accent and a German non-lexical pitch accent be defined? If ever, then the difference between their phonetic realisation may be compared. The function of a prosodic property in a language seems to be diffi-cult to quantify. Although the same prosodic cues are employed in many languages, the relevant acoustic cues and their functions vary widely from language to language.

Moreover, it is important to mention that Flege et al. (1997) themselves admitted the difficulty to predict the perceived (dis)similarity between an L1 and an L2 category even at the segmental level and pointed out the importance of an adequate assessment of perceived L1-L2 (dis)similarities and the necessity of standardised measure of per-ceived L1-L2 phonetic distance. Although establishing (dis)similarities is crucially im-portant for the SLM, to date there is no commonly accepted way of measuring cross-language (dis)similarities (Bohn, 2002) and our understanding of the exact nature of cross-language (dis)similarities is still rather limited (Strange et al., 2001). The same problem is even more acute to establish (dis)similarities of cross-language prosody as it interacts with other prosodic parameters at different linguistic levels. This owes the current situation that the focus of L2 speech models has been on segments rather than prosody, given that segments are relatively easy to describe, to analyse and to test com-pared to prosody (Mennen, 2015).

PAM: Similarly to the problem stated for the SLM, it is difficult to define perceived (dis)similarities for prosodic contrasts and to apply the PAM to predict prosodic contrasts such as the research objects of my thesis. Following the core aspects of the PAM, the perception of L2 segments crucially depends on the (dis)similarity of phonetic properties of the L2 segment and L1 categories.

20 General introduction Nevertheless, some attempts have been undertaken to apply the PAM for prosodic research (= the PAM-L2). So and Best (2008) and So and Best (2011) investigated whether L1 listeners of non-tone languages (Australian English and French) perceive L2 Mandarin tones according to their L1 prosodic categories. They asked participants to categorise the Mandarin tones into four categories “Flat pitch”, “Question”, “Statement”, and “Ex-clamation”. They reported that both English and French participants categorised non-native tones according to their L1 intonational categories, and that categorisations were based on the phonetic similarities of the pitch contours they perceived between Man-darin tones and their L1 intonational categories. Thus, they concluded that their find-ings would support an extension of the PAM to the suprasegmental domain and that L2 prosodic categories (e.g. lexical tones) would have been assimilated to the categories of listeners’ L1 prosodic system (e.g. nuclear tunes). However, the assimilation discussed in the studies appear to be induced by their methodological design. In the experiment, participants were explicitly asked to select one of the given L1 categories when hearing the L2 tones. Therefore, it might be possible that the L2 listeners actually would have not associated the L2 tones with their L1 categories when hearing them, if no categories were given to select. Moreover, the studies tell us about how acoustic correlates of lexi-cal tone assimilate to acoustic correlates of post-lexilexi-cal tone in other languages, but they still do not address whether L1 prosodic categories used at one linguistic level (e.g. at the post-lexical level) can be utilised to acquire L2 prosodic categories used at another linguistic level (e.g. at the lexical level). Following So and Best (2008) and So and Best (2011), German learners of Japanese should not have difficulties in acquiring L2 Japanese lexical pitch accent, given that a falling pitch accent in German may correspond to the phonological form of the Japanese lexical pitch accent, which is the falling one as well.

However, the falling pitch accents in both languages phonetically differ in details (see section 1.3.1). It is questionable whether the falling pitch accent in Japanese may still be assimilated to the German falling pitch accent despite the phonetic differences. Similarly to the aforementioned problem in applying the SLM to the prosodic domain, it seems to be difficult to define a perceived (dis)similarity between an L2 and an L1 prosodic cate-gory in the phonological space.

NLMM

Taking a prosodic contrast investigated in my thesis as an example; a consonant length contrast for German L2 listeners, Kuhl’s statement suggests that German learners of Japanese may be able to easily discriminate short and long consonant contrasts, when

1.5 Stages of speech processing under investigation 21