DP-model adapted to L2

General assumptions about the functioning of the DP-model have been exemplified and now this model will be discussed in the light of the learning, representation and processing of an L2 in comparison to an L1. For L1 language acquisition, Ullman, Corkin, Coppola, Hickok,

57 Growdon, Koroshetz and Pinker (1997) initially discussed that language is mapped into two different brain regions. The lexicon is considered to be stored in the declarative memory and the grammar in the procedural memory. Later, Ullman (2001) recognized that the learning, representation and processing of language may be different for L2 speakers compared to L1 speakers. The difference between L1 and L2 speakers might stem from the fact that L2 acquisition succeeds L1 acquisition. A language system is available which might affect and interfere with L2 learning, representation and processing. For this purpose, Ullman (2001) reviewed studies about L2 acquisition and processing (for example Birdsong, 1999; Johnson and Newport, 1989) and noticed that the acquisition of grammar is more affected in older language learners as well in L1 and L2 speakers than the acquisition of lexical knowledge.

Ullman (2001) concluded from these findings that age of acquisition – in this case acquiring a language in late childhood/early adulthood – plays a crucial role in L2 acquisition. This is a major difference between L1 and L2 acquisition. This distinction between lexicon and grammar has implications for the DP-model. In L2 speakers, the declarative memory system should be intact and open to access because acquiring lexical knowledge does not seem to pose any problems for L2 speakers. The access to the procedural memory system however seems to be more problematic/less available leading to problems in the acquisition of grammar. The result is that the end-state of L2 acquisition is not L1-like. In contrast, L1 speakers do not suffer from problems concerning lexical and grammatical knowledge and therefore the DP-model assumes that L1 speakers have access to declarative and procedural memory for their L1. Thus, the DP-model makes different predictions with regard to L1 and Lβ speakers’ language representation and processing.

The question arises, what causes the differences between L1 and L2 speakers and why only grammar is affected.¹³ The age of acquisition of the L2 has already been introduced as a distinguishing factor. Yet, age alone is not a satisfactory explanation. Ullman (2001) provided the explanation that there is a maturational change involved¹⁴. This implies, that before the maturational change, language should be learned identically in L1 and L2 speakers. No serious problems should arise and the mastery of language with an L1-like competence should be possible. The time before the maturational change is termed critical period. The DP-model thus assumes that tasks involving the procedural memory should be difficult to learn after the end of the critical period, leading to qualitative differences between L1 and L2 speakers.

13 To provide any answers to this question is not the purpose of this research. It is not the aim to explore why grammar and not the lexicon poses problems in L2 acquisition.

14 It is not under the scope of this research to discover the reason that causes the maturational change. It seems sufficient to assume that after a certain point in life, the organization of language changes.

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Concerning grammar, which, according to Ullman (2001), is processed in procedural memory, he (2001) does not assume that it can no longer be learned by L2 speakers, but rather that the procedural memory is no longer available or only partially available for this purpose.

He proposed that the problem of accessing the procedural memory can be circumvented by letting the declarative memory take over the function of the procedural memory. It should be kept in mind, that the declarative memory system is associated with the acquisition and representation of primarily lexical knowledge. L2 speakers who learn an L2 after the critical period should therefore rely to a greater extend on the declarative memory for the acquisition of grammar compared to L2 speakers learning an L2 before puberty, or L1 speakers. The declarative memory system is not the place where grammar is processed. Other operations that are not used in the procedural memory might be operating in the declarative memory.

Consider the acquisition of regular and irregular verbs. Regular verbs can be made up by a rule. Irregular verbs are not formed by a simple rule and therefore need to be stored in the declarative memory in both L1 and L2 speakers. The formation of regular verbs can be computed in the procedural memory. The rule underlying the formation can be stored. This way there is no need to recognise each verb form individually. If the access to the procedural system is not available for L2 speakers, this system does not support the acquisition of regular verbs. In spite of the procedural memory, the declarative memory can take over the function of the procedural memory in L2 acquisition. However, this is not a rule system meaning that the formation of regular verbs is not guided by this underlying rule. In the declarative memory, knowledge is conscious. It could be possible to store all regular verb forms or the rule underlying its formation so that regular verb forms can always be made up by explicitly using this rule. Even though L1 and L2 speakers make use of different memory systems when processing grammar – and consequently use different strategies – this does not mean, that the outcome is different in L1 and L2 speakers.

From the perspective of the DP model it can be argued that reflexive and personal pronouns are processed in the declarative memory of L2 speakers. Reflexive pronouns in a co-argument relation could in principle be processed in procedural memory, but because of the problem of the availability of this system, a syntactic chain between the pronominal element and the antecedent is impossible for L2 speakers. The declarative memory is not a rule system, which implies that a syntactic operation cannot be performed. The reflexive pronoun has to be processed by a discourse operation in the declarative memory. Features of the reflexive pronoun can be checked against all DPs. Additionally, information provided by the sentence can be used to guide interpretation. L1 speakers are not assumed to make use of such

59 information, as they are thought to have access to procedural memory and therefore be able to run a syntactic operation. Reuland (2001, 2011) assumed that a syntactic operation is cheaper, because it involves fewer computational steps. The consequence may be that reflexive pronouns could be processed faster than personal pronouns in L1 speakers, but not in L2 speakers. The personal pronoun in both L1 and L2 speakers has to be processed by discourse, which is done in declarative memory. The pronominal element might correctly be resolved, but different operations might be at work.

Ullman (2001) is not stating that L2 speakers, who started learning the L2 after the critical period, will never be able to access the procedural memory, nor does he assume that it is impossible for L2 speakers to reach L1-like competence. He emphasizes that practice with the L2 could affect the working of the DP-model. L2 speakers with more practice in the L2 are argued to be able to access the procedural memory for processing grammar. This implies that highly proficient L2 speakers should then not be different from L1 speakers in the processing, representation and localization of grammar and lexicon. In other words, Ullman (2001) makes the point that L2 speakers having learned a language after the critical period will initially rely more exhausively on the declarative memora for lexicon and grammar than young L2 and L1 speakers. Later, a shift is in principle possible, if the L2 speakers have had enough practice with the L2. With regard to the processing of pronominal elements, this implies that highly proficient L2 speakers should be able to access procedural memory and therefore process reflexive pronouns in a co-argument structure with a syntactic operation. Highly proficient L2 speakers’ processing should be similar to that of L1 speakers.

Summarizing, the DP-model makes the assumption that the separation between the declarative and the procedural memory is less clear in L2 speakers than it is in L1 speakers.

Furthermore, the processing of grammar in L2 speakers should, at least in the initial stages of L2 acquisition, be done by the declarative memory. The assumption with regard to L2 processing is, that low proficiency Lβ speakers’ processing of lexicon and grammar should not show a division of labour between the declarative and procedural memory. The division in functioning of the DP-model is thus assumed in highly proficient L2 speakers only. Lexical knowledge should be represented, processed and located in the declarative memory and grammar in procedural memory.