As the global society in which we live flows more easily across state borders, our people, cultures, companies, governments, and institutions from around the world have more contact. Borders are blurred and the importance of bi- and multi-lingualism becomes necessary to sustain this constant contact. As a result of this increase in language acquisition and teaching, much research has been devoted to exploring ways in which a diverse set of factors affects learning and acquisition. The significance of these variables lies in the impact on how we teach second languages. In a where barriers to inter-cultural and inter-linguistic interaction are being torn down, this research will have a great impact on its future.
Evolution has shown the immense importance of the capability of language in human beings. Because language allows for cooperation and the spread of technology and knowledge more easily, it has benefited the advancement in technology for humans. Pinker (1)writes that
"the shape of the human vocal tract seems to have been modified in evolution for the demands of speech. Our larynxes are low in our throats, and our vocal tracts have a sharp right angle bend that creates two independently-modifiable resonant cavities (the mouth and the pharynx or throat) that defines a large two-dimensional range of vowel sounds.... But it comes at a sacrifice of efficiency for breathing, swallowing, and chewing (Lieberman, 1984). Before the invention of the Heimlich maneuver, choking on food was a common cause of accidental death in humans, causing 6,000 deaths a year in the United States. The evolutionary selective advantages must have been very large to outweigh such a disadvantage."
While chimps have been trained to mimic human speech, Pinker points out, they do not naturally acquire it without training as humans do. Thus, humans are unique in their ability to acquire and pass on language.
More recent changes in human society have increased our need for and use of multi-lingual communication. Our world has become more global, leaving fewer realms to exist in state boundaries and expanding the number of activities involving different cultures and languages. Migration, inter-language marriages, bilingual education, multi-national corporations, and international organizations are just a few phenomena on the rise that require bilingual (or multilingual) participants. This trend has in turn spawned research into two overlapping areas-- initial language acquisition in young children and that on acquisition of subsequent languages. I will first turn to initial language acquisition.
INITIAL LANGUAGE ACQUISITION
The most important factor affecting initial language acquisition is neurological developments in the brain. Unless completely deprived of language input (see (1)) in the form of hearing others speak, or physical limitations prohibiting speech, children invariably learn to talk (1).
Pinker summarizes the first two years of neurological development relating to language use:
Before birth, virtually all neurons (nerve cells) are formed, and they migrate to their proper locations in the brain. But head size, brain weight, and thickness of the cerebral cortex (gray matter), where the synapses (junctions) subserving mental computation take place, continue to increase rapidly in the year after birth. Long-distance connections (white matter are not complete until nine months, and continue to grow in their speed-inducing myelin insulation throughout childhood. Synapses continue to develop peaking in number between nine months and two years (depending on the brain region), at which point the child has 50% more synapses that the adult. Metabolic activity in the brain reaches adult levels by nine to ten months , and soon exceeds it, peaking around the age of four. In addition, huge numbers of neurons die in utero, and the dying continues during the first two years before leveling off at age seven. Synapses whither from the age of two through the rest of childhood and into adolescence, when the brain's metabolic rate falls back to adult levels." (1)
The brain can also recover from damage to crucial language areas by reassigning functions to unaffected areas, while adults cannot perform similar types of recovery after the same types of damage (1).
While these are the most important factors affecting development of language, children can also have other characteristics that aid in rapid acquisition-- they are unselfconscious, learn clear positive advantages associated with successful communication (getting food, attention, etc.), and have no other language to fall back on. These types of advantages play a role in how fast and well children acquire language. In second language acquisition similar factors determine whether or not the language is acquired at all.
SUBSEQUENT LANGUAGE ACQUISITION
While initial language acquisition relies mainly on neurological development over time, second (and subsequent) language acquisition relies on age only in associated characteristics and not in actual brain structure. Past the age of two, brain structure and differences play only a nominal role. More relevant to second language acquisition (SLA) are four other factors: motivation, opportunity, environment, and personality.
MOTIVATION
A person's motivation behind learning a second language (L2) and the views she holds regarding the L2-speaking community both come into play in speed of SLA and degree of proficiency achieved. Motivation is differentiated along a continuum-- integrative at one end and instrumental at the other. Integrative motivation is seen in language learners whose desire to learn is rooted in wanting to become part of the L2-speaking community, wants more contact with it, or is genuinely interested in it. On the other end of the spectrum is instrumental motivation. A student who sees language as a means to obtaining some reward (good grades, employment, a diploma or for mere appreciation) would reflect instrumental motivation. Integrative motivation is more helpful in SLA and proficiency because there is more desire for interaction with the community and the language that helps acquisition. Those students with mainly instrumental motivation are less likely to seek out situations where there language skills will be needed and will be improved, like social occasions in the L2 community, readings in the L2, or friends in the L2 community.
Also, students with low views of the L2 community are likely to not see benefits in learning the language. If a language community is associated with poverty, crime or other negative characteristics, there is less motivation for students to be associated with that community.
OPPORTUNITY
Opportunity and motivation work together to affect language acquisition. Motivated students are more likely to seek out more opportunities that utilize language skills. Stephen Krashen has argued that "the learner improves and progresses... when he or she receives second language input that is one step beyond his/her current stage of linguistic competence. For example, if a learner is at stage 'i', then acquisition takes place when he/she is exposed to 'comprehensible input' that belongs to level 'i+1'" (2). The learner can still follow the conversation, but is exposed to new words or concepts. Many theorists and teachers (3) (4) (5) stress that varied and frequent comprehensible input is key to acquisition. It would make sense that the number of the opportunities the brain has to store and reinforce patterns, accents, concepts, and meanings of a language, that the better this information would be stored and processed.
ENVIRONMENT
The environment in which these opportunities take place also affects SLA. As explored before, the level of input provided has maximum effect at the 'i+1' level, In addition to this, an environment which encourages the greatest amount of use of the language is beneficial. Dulay and Burt (6) proposed that people use an 'affective filter' that "regulates how much input is received by a language processing mechanism" (6). If the affective filter is over-used, a person tries to compose grammatically perfect sentences every times she speaks, and if it is underused she speaks without regard to the 'rules' she is aware of. The optimal user of the affective filter speaks naturally and often and eventually incorporates more rules into her speech. In this way, the brain is provided with more experience and input while also progressing toward more fluent speech.
PERSONALITY
Personality can also affect SLA. In combination with environment it can act to inhibit learners or to encourage increased opportunity. Introversion has the greatest chance of negatively affecting SLA. Students that are afraid of embarrassing themselves by speaking incorrectly or by not being able to speak at all may try to avoid opportunities that would otherwise aid their learning. If teachers correct mistakes and further embarrass shy students, it may isolate students even more. Instead, repeating back the corrected statement allows feedback without a damaging student's ego. For example, if Marcia says "Yesterday I go to the store with my madre," the teacher would respond, "You went to the store with your mother yesterday?" She has effectively provided corrected input while also continuing the conversation. If a student shuts down after an outright correction then opportunity for more input and practice has been lost.
All of these external and internal characteristics affect the way in which language is acquired by the brain. Increased input, lowered anxiety, strong integrative motivation and positive environments can help processes of language acquisition progress. It is an interesting overlap between the physical processes of the brain and the more mental processes of the mind. While language acquisition is ultimately completed and stored in the brain, emotional and environmental factors greatly affect the process by which it is acquired. Because these factors and many others all interact in the acquisition of language, it is incredibly difficult to research the effect of one specific aspect. Many studies have ignored this fact and have tried to attribute too much weight to one factor, while others have undoubtedly affected the outcomes. Since single factors and how they affect acquisition cannot be completely isolated, research should be concentrated on the outcomes of certain teaching techniques. They will not be universally applicable, but will help to eliminate less effective or damaging techniques. This area of teaching will be increasingly important as our world continues to become more bilingual and multilingual.
