non-target language. Chapter 9 reviews the recent evidence relating to lan-
guage selection in bilingual language production – a lesser explored area than
bilingual language processing – and argue how measures of ERPs in particular
can help identify the locus of language selection in bilinguals. While the focus
of much of the discussion in Chapter 9 is on semantic and lexical organisation,
which are the most common domains of language explored in such studies,
Chapter 10 looks at how ERPs can help us understand the mechanisms under-
lying brigrammatism – i.e. the juxtaposition of two, often contrasting, gram-
mars in one brain – using measures of speakers’ anticipation of syntactic
violations rather than examining their responses to the violations themselves.
Much like Chapters 1, 3 and 4, Chapter 10 identifies the potential for cross-
linguistic transfer in bilingual processing, and takes a closer look at the under-
lying neural processing involved during bilingual syntactic processing as
compared to monolingual syntactic processing. This part thus provides fur-
ther evidence that bilinguals’ two languages are always activated, and that
this extends to the level of grammar.
Together, the chapters reveal the complexities of the relationship between
a bilingual’s two languages across domains, and highlight the role of linguis-
tic and extralinguistic factors in determining bilingual outcomes. The
strengths of the volume lie not only in the expertise of the authors and the
cutting-edge research methods employed in our research, but in the unique-
ness of some of our bilingual pairings (the Welsh-German dataset in Chapter
3, and the Welsh-Spanish dataset in Chapter 5 in particular) and bilingual
group comparisons (e.g. Welsh-English vs. English-Spanish in Chapter 6 and
vs. Arabic-English in Chapter 4), our explorations of hitherto lesser researched
aspects of bilingualism (e.g. Chapters 1, 2, 9 and 10), and in our in-depth
analysis of the relationship between two languages in an applied setting
(Chapters 7 and 8). The fact that the authors find linguistic interaction in
different language pairings as well as in different bilingual group compari-
sons suggests that it is possible to generalise these findings to other bilingual
populations. More importantly, the novelty of the book lies in our united
approach to answering the same research question from different disciplin-
ary perspectives, in theory and practice. The authors find, across chapters,
that the relationship between a bilingual’s two languages can be additive in
some domains and under certain conditions (e.g. Chapters 1, 4, 6, 7, 8, 9 and
10) but less so in others (Chapters 2, 3, 4 and 9). The authors also find that
the extent to which languages influence one another depends not only on
language internal factors such as typological distance (e.g. Chapters 2, 3, 4,
5, 6, 9 and 10) but also on extralinguistic factors, including linguistic domi-
nance within the individual (Chapters 1, 3, 4, 9 and 10 in particular), socio-
linguistic identity (Chapter 6) and age (e.g. Chapters 2, 4 and 5). The findings
from neuroscientific studies (Chapters 9 and 10) have direct implications for
the implementation of bilingualism in the applied setting, for example in
terms of our understanding of the costs involved in the co-activation of, and
Introduc t ion xxiii