The findings from a number of recent studies indicate that, even in cases of successful bilingual first language acquisition, the possibility remains of a certain degree of crosslinguistic influence when the choice between syntactic options is affected by discourse pragmatics. In this study we focussed on the use of referring expressions, prime candidates to test the interaction between syntax and pragmatics, and we compared the distribution of subjects and objects in the Italian and English of a bilingual child (1;10–4;6) with that of two groups of MLUw-matched monolinguals. All arguments were coded for syntactic function and for a number of discourse pragmatic features predicted to affect their realisation. Our main prediction was that unidirectional crosslinguistic influence might occur for the English–Italian bilingual child with respect to pronominal subject and object use after the instantiation of the C system. Specifically we predicted that in Italian the bilingual child might use overt pronominal subjects in contexts where monolinguals would use a null subject, and that he might use postverbal strong object pronouns in Italian instead of preverbal weak pronominal clitics. Conversely, we did not expect the overall proportion of overt objects, whether noun phrases or pronouns, to vary crosslinguistically as objects are always obligatorily overt in both languages regardless of discourse pragmatics. Our results confirmed these predictions, and corroborated the argument that crosslinguistic influence may occur in bilingual first language acquisition in specific contexts in which syntax and pragmatics interact.

In introducing this special issue of Bilingualism: Language and Cognition, we feel it is critical to clarify what we understand ‘linguistic convergence’ to mean in the context of bilingualism, since ‘convergence’ is a technical term more readily associated with the field of language contact than with the field of bilingualism (for recent discussions of the role of convergence in contact see Thomason and Kaufman, 1988; Thomason, 2001; Myers-Scotton, 2002; Clyne, 2003; Winford, 2003). Within the language contact literature, the term invites a variety of uses. Some researchers adopt a definition of convergence that requires that all languages in a contact situation change, sometimes to the extent that the source of a given linguistic feature cannot be determined (see April McMahon's commentary in this issue). For others, convergence may be more broadly defined to also apply to situations in which one language has undergone structural incursions of various sorts from contact with another.

The paper offers a model of language development, first and second, within a processing perspective. We first sketch a modular view of language, in which competence is embodied in the processing mechanisms. We then propose a novel approach to language acquisition (Acquisition by Processing Theory, or APT), in which development of the module occurs as a natural product of processing activity, without any acquisition mechanisms as such. The approach is illustrated and explicated through examples of the development of content words, derivational morphology, the functional category I with its variable features, and Case and thematic roles, as well as apparent cross-linguistic variation in processing strategies and the status of bootstrapping in the model. We then examine some possible applications to issues in second language acquisition – noticing the gap, the initial state, transfer, and the apparent limits of SLA – and finally offer a broader perspective on the model: its scope, its relations to other approaches, and its possible limits.

As an occasional visitor to the land of SLA, I found myself somewhat mystified by the approach of Truscott and Sharwood Smith (henceforth TSS). Unless I have totally misunderstood them, they are arguing against the separate existence of both a Language Acquisition Device (LAD) and a Universal Grammar (UG). But who ever thought they were two? Occasionally linguists may write about one rather than the other, but I have always assumed them to be the same thing appearing in different guises (like Christ and the Holy Ghost in Christian theology). If you have UG, why would you need LAD? Processing with the aid of UG seems the only way to go – to the extent that UG is available to SLA, an issue TSS does not directly address.

Guion, Clark, Harada and Wayland (2003) found that three factors affect English speakers' stress placement on bisyllabic non-words: syllabic structure, lexical class and stress patterns of phonologically similar real words. The current replication and extension included three groups (N = 30): native English speakers, early Spanish–English bilinguals, and late Spanish–English bilinguals. Participants produced and gave perceptual judgments on 40 non-words of varying syllabic structures in noun and verb sentence frames. A regression analysis used the three factors to predict stress placement in production and perception. All three groups showed significant effects from stress patterns of phonologically similar real words and lexical class. The effect of syllabic structure for early bilinguals was slightly different from that of native speakers and late bilinguals showed greatly reduced effects. Late bilinguals exhibited more initial stress overall, possibly due to L1 transfer. These results run counter to the prediction made by Long (1990) about age effects on phonological acquisition.

Most work investigating the role of convergence in situations of language attrition has focused on the morpho-syntactic restructuring of the dying language variety. A central concern of such research has been untangling the factors driving the restructuring with an eye towards establishing whether the changes observed are best viewed as externally driven or, by contrast, as internally motivated. A second and equally important concern of this research attempts to define the domains of the linguistic system that may be the most permeable to external influence. The present study provides a contribution to this line of research and sheds light on its two leading concerns from the domain of phonology and phonetics. Specifically, we present the results of an instrumental study of the phonological vowel system of Frenchville French and argue that this linguistic variety is undergoing a perceptually striking process of phonetic convergence with English that is motivated by the auditory and acoustic similarity between a subset of vowels in the contact languages. An interesting consequence of our analysis is that bilingual phonologies may become particularly permeable to inter-linguistic influence precisely where they are acoustically and perceptually unstable, and where they are already congruent to some degree.

Truscott and Sharwood Smith (henceforth T&SS) propose a novel theory of language acquisition, ACQUISITION BY PROCESSING THEORY (APT), designed to account for both first and second language acquisition, monolingual and bilingual speech perception and parsing, and speech production. This is a tall order. Like any theoretically ambitious enterprise, the APT shares certain properties with much that has gone before. Like the Competition Model (CM; MacWhinney, 1987, 1997; MacWhinney and Bates, 1989, inter alia) and other associative network connectionist learning models, the APT eschews a Language Acquisition Device (LAD) by treating acquisition as the strengthening of levels of representation activation. A parser can produce multiple representations of a parse string in parallel, which then ‘compete’ as analyses for an input string. Unlike the CM, however, the APT is not motivated by a solid program of empirical studies in language acquisition or cross-language processing. Nor does it strike me as theoretically coherent, for the APT, unlike the CM, assumes that knowledge of language involves knowledge of grammatical structure and that the parser makes deterministic use of Universal Grammar in the form of a Minimalist grammar. The determinism is important here; the claim to eliminate LAD hinges on it.

Simultaneous interpreting is a complex task where the interpreter is routinely involved in comprehending, translating and producing language at the same time. This study assessed two components that are likely to be major sources of complexity in SI: The simultaneity of comprehension and production, and transformation of the input. Furthermore, within the transformation component, we tried to separate reformulation from language-switching. We compared repeating sentences (shadowing), reformulating sentences in the same language (paraphrasing), and translating sentences (interpreting) of auditorily presented sentences, in a simultaneous and a delayed condition. Output performance and ear–voice span suggest that both the simultaneity of comprehension and production and the transformation component affect performance but that especially the combination of these components results in a marked drop in performance. General lower recall following a simultaneous condition than after a delayed condition suggests that articulation of speech may interfere with memory in SI.

Bullock and Gerfen show that two of the last speakers of French in Frenchville, Pennsylvania, systematically replace the French front mid round vowel (in words like deux, neuf) with the rhoticized schwa of American English, their dominant language. As the authors argue, it is unlikely that this sound change would have arisen in the speech of French speakers who were not bilingual in English.

Tests of inter-lingual homographs that have different meanings across two languages support models postulating initial non-selective access to competing language representations, e.g. Bilingual Interactive Activation (BIA) model. Most such research assessed inter-lingual homographs in the absence of connected text. Here a letter detection paradigm was used that required subjects to detect letters in words in connected text. Prior work with this paradigm suggested that readers respond to only one interpretation of an intra-lingual homograph when detecting letters. Three experiments described here indicate that letter detection patterns to inter-lingual homographs are similar, i.e. detection reflects only a context appropriate interpretation. However, the demonstration that text role, text cohesiveness and bilingual fluency affect inter-lingual letter detection (Experiments 1 and 2), and that word role affects detection even though target frequency is constant across inter-lingual meanings (Experiment 3) indicates that selectivity is in response to post-lexical processes. Thus, results are seen as compatible with tenets of the BIA model.

In this paper we present experimental evidence showing that Buenos Aires Spanish differs from other Spanish varieties in the realization of pre-nuclear pitch accents and in the final fall in broad focus declarative utterances. Whereas other Spanish varieties have been described consistently as showing late peak alignments, Buenos Aires Spanish displays early peak alignments. The alignment pattern found in Buenos Aires broad focus declarative utterances is not totally foreign to Spanish: it is attested in a quite different function, i.e. to signal contrastive focus. In addition, Buenos Aires Spanish also seems to differ from other Spanish varieties in the realization of the intonation contour in utterance-final intonational phrases, where a pronounced tendency for down-stepped peaks is observed. We argue that these patterns, which emerged at the turn of the twentieth century, and coincided with the peak of Italian immigration, are due to a combination of direct and indirect transfer from Italian. As a result, two intonational systems that were typologically similar before contact took place (Hualde, 2002) became more similar after contact, in what can be interpreted as a case of convergence.

In their keynote contribution, Truscott and Sharwood Smith offer a general model of language development from a processing perspective. As they state, their model is very ambitious: Their ‘acquisition by processing’ theory (APT) aims not only at explaining both first and second language acquisition but also real-time processing in language comprehension and production. APT takes a cross-disciplinary approach that intends to bring together research on linguistic structure and on general cognition. However, the joint contribution of linguistic and psycholinguistic approaches is mainly evident in terms of theoretical concepts (e.g. UG, syntactic rules, modules, activation) because the presented empirical evidence is limited in scope.

We examined the effects of study-abroad experience (SAE) and working-memory capacity (WMC) on the types of errors made during single-word translation from the first language to the second language, contrasting non-response with meaning errors (i.e. when individuals translate semantically-related words instead of the target word). SAE and WMC interacted; individuals with more SAE and higher WMC made as many meaning as non-response errors, whereas individuals in the other groups made more non-response than meaning errors. We conclude that SAE encourages the use of approximate translations to communicate, but only higher WMC learners can do so because this strategy requires multiple items to be maintained in memory simultaneously. A speech-production model is adapted to capture our results and demonstrate the effects of differential working memory demands on producing correct translations, meaning errors, and non-response errors.

Using evidence from first-hand experimental work and existing studies, Colantoni and Gurlekian take a tentative but encouraging step towards exploring the role of contact in explaining intonational change. Their central question is whether Buenos Aires Spanish intonation is distinctive relative to other varieties of Spanish; and if so, whether that distinctiveness is due to contact with Italian.

Acquisition by Processing Theory (APT) is a unified account of language processing and learning that encompasses both L1 and L2 acquisition. Bold in aim and broad in scope, the proposal offers parsimony and comprehensiveness, both highly desirable in a theory of language acquisition. However, the sweep of the proposal is accompanied by an economy of description that makes it difficult to evaluate the validity of key learning claims, or even how literally they are to be interpreted. Two in particular deserve comment; the first concerns the learning mechanisms responsible for adding new L2 grammatical information, and the second the theoretical and empirical status of the activation concept used in the model.

Many simultaneous bilinguals exhibit loss or incomplete acquisition of their heritage language under conditions of exposure and use of the majority language (Silva-Corvalán, 1994, 2003; Polinsky, 1997; Toribio, 2001; Montrul, 2002). Recent work within discourse-functional (Silva-Corvalán 1994) and generative perspectives (Sorace, 2000; Montrul; 2002; Tsimpli, Sorace, Heycock, Filaci and Bouba, 2003, in press) suggests that while syntax proper is impervious to language loss or attrition, syntax-related interfaces like lexical-semantics and discourse-pragmatics are not. This study investigates argument expression in adult simultaneous bilinguals who are heritage speakers of Spanish, because in this language subjects, direct, and indirect objects are regulated by syntactic, pragmatic and semantic factors. It was hypothesized that if language loss affects interface areas of competence more than the purely syntactic domains, then Spanish heritage speakers should display robust knowledge of null subjects as well as object clitics, but variable behavior in the pragmatic distribution of null vs. overt subjects, the a preposition with animate direct objects, and cases of semantically based dative clitic-doubling. Results of an oral production task administered to 24 intermediate and advanced heritage speakers and 20 monolinguals confirmed the hypotheses. With the erosion of pragmatic and semantic features, the grammars of the intermediate proficiency Spanish heritage speakers appear to display morphosyntactic convergence with English in the expression of subject and object arguments.

This keynote article proposes a new model of language development based on processing, the sole mechanism of acquisition for the Acquisition by Processing Theory (APT). The language module – adapted from Jackendoff's distinction between integration (building complex structures) and interface (facilitating information transfer at the intersections of the sub-modules) – has phonological, syntactic and conceptual processors that interact with each other, working memory and lexical entries. On the one hand, the application of Jackendoff's model to language learning bridges a gap between syntactic theory and processing. On the other hand, its breadth sometimes brings together strange bedfellows, as, for example, minimalist syntax and APT's ‘clear affinities with connectionism’ (p. 17). In order to explore this hybrid model within a focused area, I will limit my comments to a discussion of features of I(nflection), Case and thematic (theta) roles, highlighting the question of how much syntactic theory APT needs. I will suggest that the model could profit from a greater exploitation of morphological input and its role in parameter setting.

Truscott and Sharwood Smith (henceforth T&SS) attempt to show how second language acquisition can occur without any learning. In their APT model, change depends only on the tuning of innate principles through the normal course of processing of L2. There are some features of their model that I find attractive. Specifically, their acceptance of the concepts of competition and activation strength brings them in line with standard processing accounts like the Competition Model (Bates and MacWhinney, 1982; MacWhinney, 1987, in press). At the same time, their reliance on parameters as the core constructs guiding learning leaves this model squarely within the framework of Chomsky's theory of Principles and Parameters (P&P). As such, it stipulates that the specific functional categories of Universal Grammar serve as the fundamental guide to both first and second language acquisition. Like other accounts in the P&P framework, this model attempts to view second language acquisition as involving no real learning beyond the deductive process of parameter-setting based on the detection of certain triggers. The specific innovation of the APT model is that changes in activation strength during processing function as the trigger to the setting of parameters. Unlike other P&P models, APT does not set parameters in an absolute fashion, allowing their activation weight to change by the processing of new input over time. The use of the concept of activation in APT is far more restricted than its use in connectionist models that allow for Hebbian learning, self-organizing features maps, or back-propagation.

Montrul's study is an important contribution to a recently emerged research approach to the study of bilingualism and languages in contact, characterized by its sound theoretical basis and its reliance on data from different – and traditionally non-integrated – domains of language development: bilingual first language acquisition (Müller and Hulk, 2001; Paradis and Navarro, 2003; Serratrice, 2004; Serratrice, Sorace and Paoli, in press), adult second language acquisition (Filiaci, 2003; Sorace, 2003), and native language attrition (Gurel, 2002; Tsimpli, Sorace, Heycock and Filiaci, in press). The generalization that is emerging from this approach is that interfaces between syntax and other cognitive systems (i.e. discourse pragmatics, lexical-semantics) exhibit more developmental instability than narrow syntax. For L1 attrition, which is the specific focus of the paper, this means that aspects of grammar at the syntax–discourse interface are more vulnerable to attrition than purely syntactic aspects. The identification of restrictions on the domain of occurrence of attrition is consistent with much previous descriptive research on this topic (e.g. Seliger and Vago, 1991). More recently, the same conclusion has been reached by a study on individual language attrition by Tsimpli et al. (in press), who investigated knowledge of the referential pronominal system in Greek and Italian in very advanced speakers of English. In this paper, Montrul tests the generalization on second-generation speakers of Spanish – or “heritage speakers” – a bilingual group that presents different characteristics from the adult L2 speakers investigated in Tsimpli et al.'s study. In addition to referential subjects, she also focuses on a different interface area of grammar – direct objects – that had not been investigated before. In these respects, Montrul's study is a welcome development. In other respects, however, the data are less than convincing and do not allow a straightforward interpretation. My commentary focuses on three fundamental questions raised not only by this study, but also by this type of research in general. The main focus will be the expression of referential subjects since this aspect of grammar has been investigated in other studies and therefore offers the possibility of direct comparison among results.

Truscott and Sharwood-Smith's (henceforth T&SS's) paper offers an interesting set of hypotheses about one possible processing perspective in research on language acquisition. What is striking about this exposition of their model is that it ignores almost entirely the context of previous research on this issue. Embedding their exposition in its historical context would have in no way diminished the innovation entailed in their proposal. Instead it could have served as an instrument for ensuring conceptual parsimony, which in my view is flawed in this exposition.