Publications

Abstract

Empirical studies addressing the age factor in second language acquisition have mainly been concerned with a comparison of end state data (from learners before and after the closure of a putative Critical Period for language acquisition) to the native speaker norm. Based on longitudinal corpus data, this paper investigates the affect of age on end state, rate and the process of acquisition and addresses the question of whether different grammatical domains are equally affected. To this end, the paper presents summarized findings from the acquisition of word order and inflectional morphology in L2 German by Russian learners of different ages and discusses theoretical implications that can be drawn from this evidence.

Abstract

Brain-to-brain interfaces, in which brains are physically connected without the intervention of language, promise new ways of collaboration and communication between humans. I examine the narrow view of language implicit in current conceptions of brain-to-brain interfaces and put forward a constructive alternative, stressing the role of language in organising joint agency. Two features of language stand out as crucial: its selectivity, which provides people with much-needed filters between public words and private worlds; and its negotiability, which provides people with systematic opportunities for calibrating understanding and expressing consent and dissent. Without these checks and balances, brain-to-brain interfaces run the risk of reducing people to the level of amoeba in a slime mold; with them, they may mature to become useful extensions of human agency

Abstract

This entry provides some orientation and task suggestions on how to explore the perceptual world of your field site and the interaction between the cultural world and the sensory lexicon in your community. The material consists of procedural texts; soundscapes; other documentary and observational tasks. The goal of this task is to explore the perceptual world of your field site and the interaction between the cultural world and the sensory lexicon in your community.

Abstract

The Mawu people of eastern Ghana make common use of ideophones: marked words that depict sensory imagery. Ideophones have been described as “poetry in ordinary language,” yet the shadow of Lévy-Bruhl, who assigned such words to the realm of primitivity, has loomed large over linguistics and literary theory alike. The poet Ezra Pound is a case in point: while his fascination with Chinese characters spawned the ideogrammic method, the mimicry and gestures of the “primitive languages in Africa” were never more than a mere curiosity to him. This paper imagines Pound transposed into the linguaculture of the Mawu. What would have struck him about their ways of ‘charging language’ with imagery? I juxtapose Pound’s views of the poetic image with an analysis of how different layers of iconicity in ideophones combine to depict sensory imagery. This exercise illuminates aspects of what one might call ‘the ideophonic

Abstract

Mensen groeien op in verschillende omgevingen, met verschillende ervaringen en verschillende talen. Betekent dat ook dat ze verschillend denken? En als er invloed is van taal op denken, hoe ver reikt die dan? Wordt ons denken begrensd door woorden, of is de invloed meer gematigd en kunnen we er soms zelfs aan ontkomen?

Abstract

Linguistic discovery is viewpoint-dependent, just like our ideas about what is marginal and what is central in language. In this essay I consider two supposed marginalia —ideophones and interjections— which provide some useful pointers for widening our field of view. Ideophones challenge us to take a fresh look at language and consider how it is that our communication system combines multiple modes of representation. Interjections challenge us to extend linguistic inquiry beyond sentence level, and remind us that language is social-interactive at core. Marginalia, then, are not the obscure, exotic phenomena that can be safely ignored: they represent opportunities for innovation and invite us to keep pushing the edges of linguistic inquiry.

Abstract

The article analyzes the relation between Aweti and Kamayurá on different levels. Both languages belong to different branches of the subfamily “Maweti-Guarani” within the large Tupi ‘stock’. Both peoples have arrived rather late to the complex Upper Xinguan society, but probably independently and from different directions. Both resulted from mergers of different groups and suffered a dramatic demographic decline in the first half of last century. There is no concrete evidence that these groups spoke varieties of more than 2 different languages (Pre-Aweti and Pre-Kamayurá). Today, many Aweti are at least passive bilinguals with Kamayurá, their most important allies, but the opposite does not hold. The article also discusses the relations between the languages on the main structural levels. In phonology, the phoneme inventories are compared and the sound changes are listed that occurred from the hypothetical proto-language “Proto-Maweti-Guarani” to Aweti, on the one hand, and to Proto-Tupi-Guarani and further to Kamayurá, on the other. In morpho-syntax, the article offers a comparison of the person systems and of affixes in general, treating in particular the so-called ‘relational prefixes’, which do not exist in Aweti. The most important syntactic shared properties are also listed. There seem to be very little mutual lexical borrowing. In the appendix, a list of more than 60 cognates with reconstructed proto-forms is given. Key-words: Aweti; Kamayurá; Sociolinguistics; History; Phonology.

Abstract

Der vorliegende Beitrag zum Kieler Symposium1 stellt die Resultate eines Teilbereichs meiner Arbeit zum Guarani vor, nämlich einen Vorschlag zur Analyse der Personenpräfixe dieser Sprache und der mit ihnen verbundenen grammatischen Kategorien. Die im Titel angedeutete lexikographische Fragestellung bedarf einer näheren Erläuterung, die ich im Zusammenhang mit einer kurzen Darstellung der Motivation für meine Untersuchungen geben will

Abstract

A key for understanding the Upper Xingu system is the comparison of the different languages which are part of that multilingual society. This article discusses the notion ‘comparing languages’ and delineates a research program in accordance to which a fruitful comparison can be done on four levels: 1) structural (phonological and morphosyntactic), 2) lexical (semantic structure of the lexica and individual lexical items), 3) discourse (figures of speech and thought), 4) content (in particular, narratives). The language data of the project gathered so far (focusing on level 2 and 4) is described in detail: 10 comparative word lists from different semantic domains, and a core of 5 analogous texts of different genera. Finally, some general considerations are offered about how to analyze both similarities and divergence found among the compared material.

Abstract

With the present essay I pursue a threefold aim as will be explained in the following paragraphs. Since I cannot expect my readers to be familiar with the language studied, Guaran´ı, more information about this language will be given in the next subsection.

Abstract

Conclusion In this study we have examined the evidence for the exact genetic position of the Awetí language in the large Tupí family, especially evidence for an internal classification of the larger branch of Tupí called “Mawetí-Guaraní” which comprises the Tupí-Guaraní family, Awetí and Sateré-Mawé. As it turns out, we did not find any clear example of an uncommon sound change which would have happened after the separation of the antecessor of one branch but before the split between the other two. There is some just probability that Awetí belongs somewhat closer to Tupí-Guaraní within Mawetí-Guaraní (configuration A in Table 1), but we did not find any conclusive evidence. All we have are some weak indications the majority of which, however, point in this direction: • a higher number of cognates found between Awetí and proto-Tupí-Guarani; • lexicostatistic results (number of cognates in a 100-item-word-list proposed by Swadesh); • loss of long vowels in Awetí and Tupí-Guaraní, but not in Sateré-Mawé; • some sound changes suggest that in the development to Awetí and to proto-Tupí-Guaraní velar segments changes to dental segments (cf. the discussion of the correspondence set j : t : w); • possibly some of the correspondence sets given in Table 20. We consider it to be too soon to conclude that there is a branch Awetí + Tupí-Guaraní of Mawetí-Guaraní, opposed to Sateré-Mawé, but if there is any grouping, this hypothesis is most promising. 29

Abstract

This contribution explores the potentials of combining corpora of language use data with language description in e-grammars (or digital grammars). We present three directions of ongoing research and discuss the advantages of combining these and similar approaches, arguing that the technological possibilities have barely begun to be explored.

Abstract

This paper describes the verbal Tense-Aspect-Mood system of Awetí (Tupian, Central Brazil) in a Word-and-Paradigm approach. One classification of Awetí verb forms contains clear aspect categories. A second set of independent classifications renders at least four moods and contains a third major TAM classification, factuality, that has one mainly temporal category Future, while others are partially or wholly modal. Structural categories reflect the formal composition of the forms. Some forms are synthetic, ‘marked’ only by means of affixes, but many are analytic, containing auxiliary particles. With selected sample forms we demonstrate in detail the interplay of structural and functional categories in Awetí verb paradigms.

Abstract

Definition Perceptual learning in speech describes a change in the mapping from acoustic cues in the speech signal to abstract linguistic representations. Learning leads to a lasting benefit to the listener by improving speech comprehension. The change can occur as a response to a specific feature (such as a talker- or accent idiosyncrasy) or to a global degradation of the signal (such as in synthesized or compressed speech). In perceptual learning, a top-down process is involved in causing the change, whereas purely bottom-up, signal-driven phenomena are considered to be adaptation.

Abstract

This revised version supersedes all previous versions (e.g., Field Manual 2010).

Abstract

This field guide is for eliciting information about grammatical resources used in describing perceptual events and perception-based properties and states. A list of leading questions outlines an underlying semantic space for events/states of perception, against which language-specific constructions may be defined. It should be used as an entry point into a flexible exploration of the structures and constraints which are specific to the language you are working on. The goal is to provide a cross-linguistically comparable description of the constructions of a language used in describing perceptual events and states. The core focus is to discover any sensory asymmetries, i.e., ways in which different sensory modalities are treated differently with respect to these constructions.

Abstract

This article describes the grammatical resources available to speakers of Lao for describing situations that can be described broadly as ‘reciprocal’. The analysis is based on complementary methods: elicitation by means of non-linguistic stimuli, exploratory consultation with native speakers, and investigation of corpora of spontaneous language use. Typically, reciprocal situations are described using a semantically general ‘collaborative’ marker on an action verb. The resultant meaning is that some set of people participate in a situation ‘together’, broadly construed. The collaborative marker is found in two distinct syntactic constructions, which differ in terms of their information structural contexts of use. The paper first explores in detail the semantic range of the collaborative marker as it occurs in the more common ‘Type 1’ construction, and then discusses a special pragmatic context for the ‘Type 2’ construction. There is some methodological discussion concerning the results of elicitation via video stimuli. The chapter also discusses two specialised constructions dedicated to the expression of strict reciprocity.

Abstract

(from the chapter) Recognizing others' goals in the flow of interaction is complex, not only for analysts but for participants too. This chapter explores a semiotic approach, with the utterance-in-context as a basic-level unit, and where the interpreter, not the producer, is the driving force in how utterances come to have meaning. We first want to know how people extract meaning from others' communicative behavior. We then ask what are the elements of producers' formulation of communicative actions in anticipation of how others will interpret that behavior.

Abstract

Laos features a high level of linguistic diversity, with more than 70 languages from four different major language families (Tai, Mon-Khmer, Hmong-Mien, Tibeto-Burman). Mon-Khmer languages were spoken in Laos earlier than other languages, with incoming migrations by Tai speakers (c. 2000 years ago) and Hmong-Mien speakers (c. 200 years ago). There is widespread language contact and multilingualism in upland minority communities, while lowland-dwelling Lao speakers are largely monolingual. Lao is the official national language. Most minority languages are endangered, with a few exceptions (notably Hmong and Kmhmu). There has been relatively little linguistic research on languages of Laos, due to problems of both infrastructure and administration.

Abstract

This chapter discusses some of the elements of human sociality that serve as the social and cognitive infrastructure or preconditions for the use of requests and other kinds of recruitments in interaction. The notion of an agent with goals is a canonical starting point, though importantly agency tends not to be wholly located in individuals, but rather is socially distributed. This is well illustrated in the case of requests, in which the person or group that has a certain goal is not necessarily the one who carries out the behavior towards that goal. The chapter focuses on the role of semiotic (mostly linguistic) resources in negotiating the distribution of agency with request-like actions, with examples from video-recorded interaction in Lao, a language spoken in Laos and nearby countries. The examples illustrate five hallmarks of requesting in human interaction, which show some ways in which our ‘manipulation’ of other people is quite unlike our manipulation of tools: (1) that even though B is being manipulated, B wants to help, (2) that while A is manipulating B now, A may be manipulated in return later; (3) that the goal of the behavior may be shared between A and B, (4) that B may not comply, or may comply differently than requested, due to actual or potential contingencies, and (5) that A and B are accountable to one another; reasons may be asked for, and/or given, for the request. These hallmarks of requesting are grounded in a prosocial framework of human agency.

Abstract

People of all cultures have some degree of concern with categorizing types of communicative social action. All languages have words with meanings like speak, say, talk, complain, curse, promise, accuse, nod, wink, point and chant. But the exact distinctions they make will differ in both quantity and quality. How is communicative social action categorised across languages and cultures? The goal of this task is to establish a basis for cross-linguistic comparison of native metalanguages for social action.

Abstract

This version is reprinted from the 2010 Field Manual

Abstract

This Field Manual entry has been superceded by the 2009 version: https://doi.org/10.17617/2.883564

Abstract

Reciprocity lies at the heart of social cognition, and with it so does the encoding of reciprocity in language via reciprocal constructions. Despite the prominence of strong universal claims about the semantics of reciprocal constructions, there is considerable descriptive literature on the semantics of reciprocals that seems to indicate variable coding and subtle cross-linguistic differences in meaning of reciprocals, both of which would make it impossible to formulate a single, essentialising definition of reciprocal semantics. These problems make it vital for studies in the semantic typology of reciprocals to employ methodologies that allow the relevant categories to emerge objectively from cross-linguistic comparison of standardised stimulus materials. We situate the rationale for the 20-language study that forms the basis for this book within this empirical approach to semantic typology, and summarise some of the findings.

Abstract

The mysterious human propensity for acquiring speech and language has fascinated scientists for decades. A substantial body of evidence suggests that this capacity is rooted in aspects of neurodevelopment that are specified at the genomic level. Researchers have begun to identify genetic factors that increase susceptibility to developmental disorders of speech and language, thereby offering the first molecular entry points into neuronal mechanisms underlying human vocal communication. The identification of genetic variants influencing language acquisition facilitates the analysis of animal models in which the corresponding orthologs are disrupted. At face value, the situation raises aperplexing question: if speech and language are uniquely human, can any relevant insights be gained from investigations of gene function in other species? This chapter addresses the question using the example of FOXP2, a gene implicated in a severe monogenic speech and language disorder. FOXP2 encodes a transcription factor that is highly conserved in vertebrate species, both in terms of protein sequence and expression patterns. Current data suggest that an earlier version of this gene, present in the common ancestor of humans, rodents, and birds, was already involved in establishing neuronal circuits underlying sensory-motor integration and learning of complex motor sequences. This may have represented one of the factors providing a permissive neural environment for subsequent evolution of vocal learning. Thus, dissection of neuromolecular pathways regulated by Foxp2 in nonlinguistic species is a necessary prerequisite for understanding the role of the human version of the gene in speech and language.

Abstract

Relative clause processing depends on the grammatical role of the head noun in the subordinate clause. This has traditionally been explained in terms of cognitive limitations. We suggest that structure-related processing differences arise from differences in experience with these structures. We present a connectionist model which learns to produce utterances with relative clauses from exposure to message-sentence pairs. The model shows how various factors such as frequent subsequences, structural variations, and meaning conspire to create differences in the processing of these structures. The predictions of this learning-based account have been confirmed in behavioral studies with adults. This work shows that structural regularities that govern relative clause processing can be explained within a usage-based approach to recursion.

Abstract

Relative clauses are a syntactic device to create complex sentences and they make language structurally productive. Despite a considerable number of experimental studies, it is still largely unclear how children learn relative clauses and how these are processed in the language system. Researchers at the MPI for Psycholinguistics used a computational learning model to gain novel insights into these issues. The model explains the differential development of relative clauses in English as well as cross-linguistic differences

Abstract

This chapter connects the grammar of the first person collective pronoun in the Cha’palaa language of Ecuador with its use in interaction for collective reference and social category membership attribution, addressing the problem posed by the fact that non-singular pronouns do not have distributional semantics (“speakers”) but are rather associational (“speaker and relevant associates”). It advocates a cross-disciplinary approach that jointly considers elements of linguistic form, situated usages of those forms in instances of interaction, and the broader ethnographic context of those instances. Focusing on large-scale and relatively stable categories such as racial and ethnic groups, it argues that looking at how speakers categorize themselves and others in the speech situation by using pronouns provides empirical data on the status of macro-social categories for members of a society

Abstract

This paper investigates the lexical semantics and relative distributions of verbs describing putting and taking events in Kuuk Thaayorre, a Pama-Nyungan language of Cape York (Australia). Thaayorre put/take verbs can be subcategorised according to whether they may combine with an NP encoding a goal, an NP encoding a source, or both. Goal NPs are far more frequent in natural discourse: initial analysis shows 85% of goal-oriented verb tokens to be accompanied by a goal NP, while only 31% of source-oriented verb tokens were accompanied by a source. This finding adds weight to Ikegami’s (1987) assertion of the conceptual primacy of goals over sources, reflected in a cross-linguistic dissymmetry whereby goal-marking is less marked and more widely used than source-marking.

Abstract

To understand the underlying principles of categorisation and classification of sensory input semantic analyses must be based on both language and culture. The senses are not only physiological phenomena, but they are also linguistic, cultural, and social. The goal of this task is to explore and describe sociocultural patterns relating language of perception, ideologies of perception, and perceptual practice in our speech communities.

Abstract

This chapter explores what L2 learners' gestures reveal about L2 grammar. The focus is on learners’ difficulties with maintaining reference in discourse caused by their incomplete mastery of pronouns. The study highlights the systematic parallels between properties of L2 speech and gesture, and the parallel effects of grammatical development in both modalities. The validity of a communicative account of interlanguage grammar in this domain is tested by taking the cohesive properties of the gesture-speech ensemble into account. Specifically, I investigate whether learners use gestures to compensate for and to license over-explicit reference in speech. The results rule out a communicative account for the spoken variety of maintained reference. In contrast, cohesive gestures are found to be multi-functional. While the presence of cohesive gestures is not communicatively motivated, their spatial realisation is. It is suggested that gestures are exploited as a grammatical communication strategy to disambiguate speech wherever possible, but that they may also be doing speaker-internal work. The methodological importance of considering L2 gestures when studying grammar is also discussed.

Abstract

Gestures, the symbolic movements speakers perform while they speak, are systematically related to speech and language at multiple levels, and reflect cognitive and linguistic activities in non-trivial ways. This chapter presents an overview of what gestures can tell us about the processes of second language acquisition. It focuses on two key aspects, (a) gestures and the developing language system and (b) gestures and learning, and discusses some implications of an expanded view of language acquisition that takes gestures into account.

Abstract

Using a poorly mastered second language (L2) in interaction with a native speaker is a challenging task. This paper explores how L2 speakers and their native interlocutors together deploy gestures and speech to sustain problematic interaction. Drawing on native and non-native interactions in Swedish, French, and Dutch, I examine lexical, grammatical and interaction-related problems in turn. The analyses reveal that (a) different problems yield behaviours with different formal and interactive properties that are common across the language pairs and the participant roles; (b) native and non-native behaviour differs in degree, not in kind; and (c) that individual communicative style determines behaviour more than the gravity of the linguistic problem. I discuss the implications for theories opposing 'efficient' L2 communication to learning. Also, contra the traditional view of compensatory gestures, I will argue for a multi-functional 'hydraulic' view grounded in gesture theory where speech and gesture are equal partners, but where the weight carried by the modalities shifts depending on expressive pressures.

Abstract

This study focuses on the effect of the semantics of placement verbs on placement event representations. Specifically, it explores to what extent the semantic properties of habitually used verbs guide attention to certain types of spatial information. French, which typically uses a general placement verb (mettre, 'put'), is contrasted with Dutch, which uses a set of fine-grained (semi-)obligatory posture verbs (zetten, leggen, 'set/stand', 'lay'). Analysis of the concomitant gesture production in the two languages reveals a patterning toward two distinct, language-specific event representations. The object being placed is an essential part of the Dutch representation, while French speakers instead focus only on the (path of the) placement movement. These perspectives permeate the entire placement domain regardless of the actual verb used.

Abstract

This paper explores the linguistic encoding of placement and removal events in Swedish. Drawing on elicited spoken data, it provides a unified approach to caused motion descriptions. The results show uniform syntactic behaviour of placement and removal descriptions and a consistent asymmetry between placement and removal in the semantic specificity of verbs. The results also reveal three further semantic patterns, pertaining to the nature of the relationship between Figure and Ground, that appear to account for how these event types are characterised, viz. whether the Ground is represented by a body part of the Agent; whether the Figure is contained within the Ground; or whether it is supported by the Ground.

Abstract

A key problem in studies of bilingual linguistic cognition is how to probe the details of underlying representations in order to gauge whether bilinguals' conceptualizations differ from those of monolinguals, and if so how. This chapter provides an overview of a line of studies that rely on speech-associated gestures to explore these issues. The gestures of adult monolingual native speakers differ systematically across languages, reflecting consistent differences in what information is selected for expression and how it is mapped onto morphosyntactic devices. Given such differences, gestures can provide more detailed information on how multilingual speakers conceptualize events treated differently in their respective languages, and therefore, ultimately, on the nature of their representations. This chapter reviews a series of studies in the domain of (voluntary and caused) motion event construal. I first discuss speech and gesture evidence for different construals in monolingual native speakers, then review studies on second language speakers showing gestural evidence of persistent L1 construals, shifts to L2 construals, and of bidirectional influences. I consider the implications for theories of ultimate attainment in SLA, transfer and convergence. I will also discuss the methodological implications, namely what gesture data do and do not reveal about linguistic conceptualisation and linguistic relativity proper.

Abstract

Reading is a cultural invention that needs to recruit cortical infrastructure that was not designed for it (cultural recycling of cortical maps). In the case of reading both visual cortex and networks for speech processing are recruited. Here I discuss current views on the neurobiological underpinnings of spoken language that deviate in a number of ways from the classical Wernicke-Lichtheim-Geschwind model. More areas than Broca’s and Wernicke’s region are involved in language. Moreover, a division along the axis of language production and language comprehension does not seem to be warranted. Instead, for central aspects of language processing neural infrastructure is shared between production and comprehension. Arguments are presented in favor of a dynamic network view, in which the functionality of a region is co-determined by the network of regions in which it is embedded at particular moments in time. Finally, core regions of language processing need to interact with other networks (e.g. the attentional networks and the ToM network) to establish full functionality of language and communication. The consequences of this architecture for reading are discussed.

Abstract

Beim Sprechen und beim Sprachverstehen findet man die Wortbedeutung im Gedächtnis auf und kombiniert sie zu größeren Einheiten (Unifikation). Solche Unifikations-Operationen laufen auf unterschiedlichen Ebenen der Sprachverarbeitung ab. In diesem Beitrag wird ein Rahmen vorgeschlagen, in dem psycholinguistische Modelle mit neurobiologischer Sprachbetrachtung in Verbindung gebracht werden. Diesem Vorschlag zufolge spielt der linke inferiore frontale Gyrus (LIFG) eine bedeutende Rolle bei der Unifi kation

Abstract

We review data and hypotheses dealing with the mental representations for perceived and produced speech that infants build and use over the course of learning a language. In the early stages of speech perception and vocal production, before the emergence of a receptive or a productive lexicon, the dominant picture emerging from the literature suggests rather non-analytic representations based on units of the size of the syllable: Young children seem to parse speech into syllable-sized units in spite of their ability to detect sound equivalence based on shared phonetic features. Once a productive lexicon has emerged, word form representations are initially rather underspecified phonetically but gradually become more specified with lexical growth, up to the phoneme level. The situation is different for the receptive lexicon, in which phonetic specification for consonants and vowels seem to follow different developmental paths. Consonants in stressed syllables are somewhat well specified already at the first signs of a receptive lexicon, and become even better specified with lexical growth. Vowels seem to follow a different developmental path, with increasing flexibility throughout lexical development. Thus, children come to exhibit a consonant vowel asymmetry in lexical representations, which is clear in adult representations.

Abstract

Originally published in Diachronica 27:2 (2010) One attempt at explaining why some language families are large (while others are small) is the hypothesis that the families that are now large became large because their ancestral speakers had a technological advantage, most often agriculture. Variants of this idea are referred to as the Language Farming Dispersal Hypothesis. Previously, detailed language family studies have uncovered various supporting examples and counterexamples to this idea. In the present paper I weigh the evidence from ALL attested language families. For each family, I use the number of member languages as a measure of cardinal size, member language coordinates to measure geospatial size and ethnographic evidence to assess subsistence status. This data shows that, although agricultural families tend to be larger in cardinal size, their size is hardly due to the simple presence of farming. If farming were responsible for language family expansions, we would expect a greater east-west geospatial spread of large families than is actually observed. The data, however, is compatible with weaker versions of the farming dispersal hypothesis as well with models where large families acquire farming because of their size, rather than the other way around.

Abstract

Whitesands is an Oceanic language of the southern Vanuatu subgroup. Like the related languages of southern Vanuatu, Whitesands has developed a clause-linkage system which monitors referent continuity on new clauses – typically contrasting with the previous clause. In this chapter I address how the construction interacts with topic continuity in discourse. I outline the morphosyntactic form of this anaphoric co-reference device. From a functionalist perspective, I show how the system is used in natural discourse and discuss its restrictions with respect to relative and complement clauses. I conclude with a discussion on its interactions with theoretical notions of information structure – in particular the nature of presupposed versus asserted clauses, information back- and foregrounding and how these affect the use of the switch-reference system