HOW DO INFANTS CRACK THE SOUND

     They perform frequency analyses.  Take for example the sound sequence “What a pretty baby you’re”.  Through continuous exposure to human language _ babbling humans produce 10,000 words and more I a single hour.  Infants progressively understand the syllables which are part of the same word to tend to follow on another predictably [prêt_ty, ba_by], where as syllables that follow one another less frequently are word boundaries [a_prêt, ty_ba.

     This type of frequency analysis is depending on a well functioning memory that accumulates an ever-growing number of words and, of course extensive training.  The problem is speed.  As human speech can produce three and more words/second, there is little time for either childish astonishment or for adult considerations such as ‘what does that word exactly mean?, “is the verb in the present or past tense?, What the hell is that grammatical structure? Etc.  All full speed speech comprehension is therefore a triple challenge; slicing human speech into digestible units, endowing them with meaning by matching the segments with thousands of existing words stored in your brain dictionary, and, finally, doing all this without giving it a second thought.  Fortunately, our brain is genetically programmed to do these mental acrobatics, and as you have already done it once, when you learned your native language, you can do it again with other languages as often as you want.  To see what it looks like when your auditory brain cortex works at full speed, put your brain into a PET scanner.  Through training is paramount.  In experience, it took around 1500 to 2000 hours of intense listening to achieve semi perfect sequencing abilities, both in French and Italian.  Amazingly the results were similar for Arabic, a language so totally different from anything than other languages.  This seems counterintuitive because in Arabic, one needed to learn at least three times as many words as in Italian, and raises a couple of questions:  Could the time of exposure that is needed to achieve full sequencing abilities – 1500 hours would translate into 6,4 and 2 hours per day over a period of 9,12 and 24 months, respectively, be a human constant?  Should our speech reconviction abilities be independent of the type of language we learn?  Perhaps even relatively immune to the effect of ageing?  And are young children truly superior to adults in worked segmenting or do they simply dedicate more time to listening than adults?  Some of these questions will be answered by future research, but I am inclined to accept that there is a physiological threshold for human brain to get wired to the ability of dissecting the sounds of new languages.  You would need a minimum of time to perform this task, but you wouldn’t need much longer than that.  You are now able to solve the close to zero understanding after years of school problem that we exposed at the beginning of this chapter

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