Bilingual Preschool guru, Ana Lomba, has written an excellent explanation that addresses concerns parents often have about bilingual education.
Here is the excerpt, taken from her book Spanish for Preschoolers E Guide:
Myth #1: Young children may get confused if learning in two languages Many people may believe this because young bilingual children do mix their languages. However, this is normal and to be expected, not something to worry about. ALL, and I mean ALL ONE HUNDRED PERCENT of bilingual children mix their two languages (or three or four) at times. This does not mean that they are confused. Quite the opposite, the process of sifting two languages has been shown to do wonders to the executive area of the brain (the “Prefrontal Cortex,” which controls some of the most sophisticated human forms of expression). As they grow up, bilingual children become increasingly more adept at controlling the two languages and using one or the other (or both) on demand.
Myth #2: Children learning two languages are slower linguistically or academically. People may believe this because young bilingual children have less vocabulary than monolinguals in either of the two languages. However, when the vocabulary of the two languages is put together, bilingual children know the same amount of words, on average, as monolinguals. Of course, bilingual children keep adding vocabulary in both languages as time goes on.
Let’s take a look at the following scenario. A young bilingual child may know the colors “red, azul, yellow, amarillo, morado, green, verde” and a monolingual child may know “green, blue, red, purple, orange.” Both children can identify five colors, and the bilingual child actually knows the name of two of those colors in the two languages. However, If tested with the typical battery test created for English speakers, the bilingual child will seem to know only three colors, as opposed to the monolingual who knows five. These tests do not measure the language wealth of bilingual children correctly.Please also be aware that many tests advertised as “bilingual” do not do a good job of measuring bilingual children either [This was an important topic of discussion at a conference at Princeton University].
So bilingual kids are not slower than monolinguals. In fact, studies have shown that children who have developed an advanced proficiency in two languages and cultures do not struggle more academically than monolingual children. Moreover, children who have developed strong proficiency in two languages many times end up surpassing monolinguals in math and even in English – and on top of that they speak two languages!
Myth #3: Young Children Are Sponges Young children have auditory advantages over adults. It has been said that “babies are citizens of the world” because newborn babies can hear all the different sounds of human languages. However, this amazing ability is quickly trimmed out in favor of the language or languages to which the baby is exposed to on a regular basis. Adults, on the other hand, have trouble detecting foreign language sounds.
All of the above being said, children are not sponges. Even children growing up in bilingual homes do not always learn their home language well. Some do not even speak it (they have become “passive bilinguals”).
Myth # 4: It Is Better to Wait Until They Are Older Not a good way to go! As a matter of fact, world language instruction has traditionally been introduced in high school with very dismal results (the grammar approach so frequently used in high school has not exactly helped either). Consultant Greg Duncan compared world languages education in the USA to an inverted pyramid: schools offer the least amount of instruction (if any) at the prime time for learning languages (early childhood), and the largest amount of instruction at one of the most difficult times for learning languages (high school). With such a weak foundation, it is no wonder that the pyramid tumbles and falls.
There are many advantages for starting early. Here are a few:
• Auditory and oral motor. As we mentioned above, young children do indeed have auditory advantages over older children and adults. Dr. Patricia Kuhl has done many studies on the issue. I invite you to watch her video presentation “The Linguistic Genius of Babies.” Some people dismiss these advantages as not important, but as time goes on and you lose them it becomes increasingly harder to reach a level of pronunciation that will be understood by natives. Sometimes a thick accent interferes so much that native speakers of the language cannot understand what the person is saying. This is even more of an obstacle when the rhythm and intonation (i.e. the “prosody”) of the languages is very different. For example, this is very much the case when English speakers learn Mandarin and vice versa, but it can happen with Spanish too.
•“Affective Filter” (Stephen Krashen). The younger the child, the less impact factors such as social pressure and self‐awareness have on classroom performance (these factors are at their peak in middle school and high school). As a matter of fact, most toddlers and preschoolers do not even blink about playing in a different language and they find it fun!
•Learning dynamics. Starting late is not a good strategy for schools and it is even worse for homes. My inbox is full of e‐mails from bilingual parents who waited to introduce their home language to their children thinking that they would get confused, and now find it very difficult to make up for lost time. Unfortunately, it is very hard to change the home language dynamics when children are older (but not impossible). In general, the earlier children get used to a language‐learning routine the easier it will be for everyone involved.
•Brain development. Learning a language is one of the best exercises for the brain, and a growing number of studies are showing its effects on cognition and other areas of human development. While this is true for all ages, obviously we may want to stimulate our children and provide them with the best possible educational experiences from the very beginning.
•Time. Finally, even with the best strategies and methods, it takes many years to acquire an advanced level in a language. Therefore, the earlier the start, the better the chances of becoming fluent.