Assume you come across a morphologically-complex Japanese word such as “.” Even if
you have absolutely no knowledge of Japanese at all, and are therefore completely
insensitive to the word's morphological structure, you might still be able to distinguish
between the stem “” and the affix “.” This is because in Japanese, stems are typically
written in Kanji, while affixes are written in Hiragana, with the surface form differences
between these two scripts being distinct enough that they might even be noticeable
for someone without any knowledge of Japanese. As a result, you might actually be
able to “decompose” the word, but this decomposition process obviously does not operate
on morphological units. Instead, you simply make use of the fact that, in addition
to being morphological units, the head “” and the affix “” also constitute units on
a completely different level; they are at the same time also orthographic units.
How is this (admittedly rather far-fetched) example related to De Grauwe et al. (2014)
study on morphological decomposition in non-native (L2) speakers? In their fMRI experiment,
De Grauwe and colleagues convincingly show that L2 speakers of Dutch, just as native
speakers, are able to decompose transparent derived verbs such as “opstaan” into the
head “staan” and the modifier “op.” Based on these findings, the authors argue against
accounts of L2 morphological processing which assume qualitative differences between
native speakers and L2 speakers with regard to morphological decomposition.
In De Grauwe's study, stems and affixes were of course not written in different scripts.
However, just as in the Japanese example, the head “staan” and the modifier “op” in
a Dutch word such as “opstaan” are not only morphological units, but also constitute
units on other linguistic levels. First, at least for the vast majority of the materials
used in De Grauwe's study, head and modifier are also existing lexical units. Specifically,
“op” is a Dutch preposition, while “staan” is a verb. For separable verbs (which constitute
55 out of 70 verbs used in the experiment), this is actually the case by default,
assuming that such verbs are either “phrasal constructs” (Booij, 1990) or derived
through incorporation of a preposition into a verb (Van Riemsdijk, 1978). As a result,
modifiers in separable verbs automatically also have to be existing words of their
own. Second, “op” and “staan” also constitute syntactic units (Booij, 2002). While
verbs are usually syntactic islands (i.e., a syntactic operation such as inflection
is normally conducted on the entire verb), separable verbs are an exception to this;
for example, in order to produce a grammatically correct Dutch sentence based on the
verb “opstaan,” such as “Marie staat op,” the formulator has to separate head and
modifier, and subsequently perform different syntactic operations (e.g., inflecting
the head, moving each unit to its correct position in the sentence) on each of the
two.
Thus, while the effects reported in De Grauwe's study presumably involve a form of
decomposition, the particular properties of the derived verbs used in the study raise
the question whether this decomposition mechanism really operates on morphological
units. In other words, even a parser which is completely insensitive to morphology
might be able to decompose “opstaan” into “op” and “staan,” provided that it has access
to either information about syntactic properties of separable verbs or to a lexicon
which contains separate entries for “op” and “staan.”
A possible counter-argument against this is based on the particular area for which
the decomposition effect occurred in the fMRI study. De Grauwe and colleagues correctly
point out that the effect occurred in the LIFG, an area which, in several previous
papers, has been found to play a role in morphological decomposition. However, it
could simply be that the LIFG is generally involved in all sorts of decomposition
processes. The same knife can theoretically be used to cut all sorts of different
things into pieces.
Given these particular linguistic properties of their materials, how does De Grauwe's
study relate to the current debate about L1/L2 differences in morphological processing?
While previous behavioral studies investigating the L2 processing of derived forms
(e.g., Silva and Clahsen, 2008; Clahsen and Neubauer, 2010; Diependaele et al., 2011;
Kirkici and Clahsen, 2013) have come to different conclusions about L2 processing,
all of these studies have discussed their findings with reference to the early morpho-orthographic
segmentation mechanism proposed by Rastle et al. (2004) and Marslen-Wilson (2007).
Crucially, this account assumes a decomposition mechanism which operates specifically
on morphological units (in Rastle's case, morphemes; in Marslen-Wilson's case, affixes).
Unlike De Grauwe and colleagues, the L2 studies mentioned above used derived forms
in which stems and affixes constitute units only at the morphological level, and also,
through appropriate control conditions, went to great lengths to ensure that priming
effects are morphological in nature. Thus, while De Grauwe and colleagues interpret
their findings as evidence against L1/L2 differences, the linguistic properties of
their materials make it difficult to discuss their findings with reference to these
previous studies. In this respect, behavioral studies which have found similar priming
effects for derived forms in L1 and L2 speakers (e.g., Diependaele et al., 2011) can
possibly be considered more direct evidence against the idea of fundamental differences
between L1 and L2 processing. Additionally, de Grauwe's study also differs from these
previous studies with regard to the methodological approach (long-lag priming vs.
masked priming) and with regard to the possible role of the L1 in L2 processing (all
stimuli were Dutch/German cognates), making the studies difficult to compare.
Importantly, these issues do not diminish De Grauwe's contribution to the field in
any way. Their fMRI study quite convincingly shows that L2 speakers do not have a
general problem with the decomposition mechanism per se. Also, De Grauwe's claims
about the processing of the particular class of verbs investigated in the study, and
the lack of fundamental L1-L2 differences with regard to these verbs, remain valid.
The key question is whether these findings can be generalized from this particular
verb class to all derivations, or whether such verbs possess specific linguistic properties
which make them uniquely different from other types of morphologically-complex forms.
Hence, it would be interesting to see whether L2 speakers show similar effects for
types of morphologically-complex words in which stems and affixes only constitute
units at the morphological level, such as derived nominalizations or even inflected
forms.
Conflict of interest statement
The author declares that the research was conducted in the absence of any commercial
or financial relationships that could be construed as a potential conflict of interest.