It is not everyday that you can step back from the academic field you work in and see it as it is at that point in time. I had the opportunity of doing so as I was preparing a general introduction to the psycholinguistics of bilingualism with my Pennsylvania State University colleague, Professor Ping Li.
Our book, The Psycholinguistics of Bilingualism, benefited from the contribution of a small number of guest authors, themselves internationally recognized experts in their respective domains. It covers spoken and written language processing, language acquisition (both simultaneous and successive), cognition and the bilingual brain. It is written in such as way as to make issues accessible to non-specialists.
Among the many findings that are discussed (I have chosen a few not already dealt with in this blog), some had been proposed in the literature but had not been studied empirically until recently. The first is that language processing is a dynamic process that involves just one language at a moment in time and several languages at other moments. The position that has been prominent in recent years is that the bilingual's languages are all active, and hence intervene, even though only one is being used. But this is simply too broad a conclusion and we now know that the reality is much more subtle than that.
Depending on the context, both linguistic and environmental, the interlocutors, the main language being used (is it the stronger language?) as well as a series of methodological considerations present in experimental settings, it has become apparent that either only one language is involved in such activities as speaking, listening or reading, or several languages can be.
A related issue, but more closely linked to language knowledge, is that the bilingual's languages influence one another in a permanent way. It has been known for a long time that a stronger language will influence the weaker language at the level of pronunciation and grammar (see here). However, we now know that this is also the case at all other levels of language. Thus, Temple University researcher Aneta Pavlenko, among others, has clearly shown that conceptual transfers exist also at the level of meaning. This can be seen, for instance, when certain types of Russian-English bilinguals (e.g. childhood bilinguals whose L2 English affects their L1 Russian), speaking Russian, call handleless paper containers a "chashka", influenced by English "cup", whereas native speakers of Russian would call it a "stakan" (glass).
Another aspect is that as a second language is used increasingly, processing strategies and operations change from those largely based on the first language to those normally used with the second language. But for some aspects it may be too late depending on when the person became bilingual. For example, Delphine Guillelmon and I have shown that even though late English-French bilinguals may make very few gender errors when speaking French (e.g. saying "la bateau" instead of "le bateau"), as listeners they cannot make use of the "le" / "la" cue to activate maculine or feminine nouns in their internal lexicon and hence facilitate their comprehension. Thus, there is no time difference in their recognition of "bateau" when preceded by erroneous "la" or correct "le". It is as if they are perceptually blind to this information.
One interesting point that translators and interpreters have long been aware of without benefiting from research evidence is that translation pairs generally do not share meanings completely. Aneta Pavlenko's 2009 model of lexical organization in bilinguals reflects this. It also integrates the fact that conceptual representations can be completely language-specific. This means that some words in one of the bilingual's languages cannot be translated by means of a single word in the other language and requires a circumlocution instead. Thus, for example, words such as "frustration" and "privacy" have no ready equivalent in Russian.
At the level of the bilingual brain, Ping Li bases himself on imaging studies to argue that there is no simple answer as to whether common or distinct neural systems underlie the representation or processing of the bilingual's languages. A number of variables such as age of acquisition of a language, proficiency in the language, cross-language overlap between the bilingual's languages, levels of analysis, and so on, seem to modulate the functional activities of the bilingual brain.
Admittedly, the psycholinguistics of bilingualism is still a rather new field as compared to better established domains (the word "psycholinguistics" was coined some sixty years ago only). It contains areas hardly touched upon such as the impact of the functions of the bilingual's languages. It will be interesting in the years to come to examine the processing and cognitive consequences of the fact that bilinguals use different languages in different domains of life, for different purposes and with different people (see here). Another issue concerns biculturalism; some bilinguals are bicultural whereas others are not (see here) and this will have an impact on the experimental and imaging findings that are obtained.
This said, and as we show in our book, much has already been accomplished by dedicated psycholinguists throughout the world. May many other discoveries about the bilingual mind and brain be made in the future!
François Grosjean & Ping Li (2013). The Psycholinguistics of Bilingualism. Hoboken, NJ: Wiley-Blackwell. (With contributions by Ellen Bialystok and Raluca Barac, Annette M. B. de Groot, Rosa M. Manchón and Virginia Yip).
Aneta Pavlenko (ed.; 2009). The Bilingual Mental Lexicon: Interdisciplinary Approaches. Bristol: Multilingual Matters.
"Life as a bilingual" posts by content area.
François Grosjean's website.