英语语音-unit-2-English-Front-Vowels-Central-Vowels

EnglishFrontVowels&CentralVowelsEnglishvowelsVowelsaresoundsinwhichthereisnoobstructiontotheflowofairasitpassesfromthelarynx(喉）tothelipsinthepronunciation.Thereare20vowelsinEnglish,amongwhich12arepurevowelsand8arediphthongs（双元音）.Englishvowels&vowelclassificationTheEnglishpurevowelscanbeclassifiedaccordingtotheheightoftheraisedpartofthetonguethepartofthetongueraisedthepositionofthelipsThreefactorsforthedescriptionofEnglishvowelsI.Theheightofthebodyofthetongue–highestpointoftongue(verticalaxis);II.Thefront-backpositionofthetongue–highestpointoftongue(horizontalaxis);III.Thedegreeofliprounding-lippostureFourfrontvowelsTherearefourfrontvowelsinEnglish:/i:/,/ı/,/e/and/æ/.Thereasonthesearecalledfrontvowelsisthatthetonguebodyisshiftedforward,causingthevowelstobeproducedinthefrontofthemouth.Forthetwovowelsinthehighfrontspace,/i:/and/ı/,thetongueisclosetothehardpalate(上颚).Likewise,forthelowvowel/æ/thetongueisnearlyflatandthelowerjawmoreopenthanfortheotherfrontvowels.TonguepositionsforEnglishfrontandcentralvowels(unrounded):/i:/&/ı//i:/isaverycommonsoundinthelanguagesintheworld.Itismadebyraisingthebodyofthetonguefromitsrestpositionandshiftingitforward.The/ı/soundismadebyloweringthetongueslightlyfromthehigh-frontpositionfor/i:/.Besides,/i:/isamuchmoretensesoundthan/ı/.ThefactthatEnglishhasthesetwohighfrontvowels,differentiatedbymuscletensionintherootofthetongue,setsitapartfromChineseandmanylanguagesoftheworld.Both/i:/and/ı/canoccurininitial,medial,andfinalpositionsinwords.VerylittledifficultyshouldbeencounteredbytheChineselearnersinthepronunciationof/i:/,but/ı/isaproblemsound.Itiseasyforthelearnerstodetectthedifferenceinlength.Whatcountshere,however,isthedifferenceinquality.Itisthereforeimportanttopointoutthefactthattopronounceacorrect/ı/,youneedto1)loweryoutonguealittlebitfromthepositionfor/i:/,and2)makeitalax（松弛的）soundinsteadofatensesoundlike/i:/./e/&/æ//e/isalsoanEnglishvowelwithhighfrequencyofoccurrence.Thetonguebodyisshiftedforwardinthemid-plane./æ/isproducedbyshiftingthebodyofthetongueforwardfromitsrelaxedstate,andloweringitfromthepositionfor/e/.Itisthelowestofthefrontvowels./e/and/æ/donotoccurinfinalpositioninEnglishwords./e/and/æ/arenotreallyproblemsoundsfortheChineselearners,butmanyofthemfailtomakeacleardistinctionbetweenthetwointheirspeech.Thedifficultyisthattheyhavetomakethecleardistinctionconsistent.TwocentralvowelsTherearetwocentralvowelsinEnglish:/з:/and/ə/.Theyarecalledcentralvowelsbecausetheytendtobeproducedatapointmidwaybetweenthefrontandbackvowelsandbetweenthehighandlowvowels.i:eIæз:əhighmid-highmid-lowlowfrontcentralbackVowelCharts:EnglishFrontVowels&CentralVowels1DemoofPronunciationPower/з:/and/ə//з:/and/ə/arecentralvowels./з:/ismadewiththetongueintheapproximatemiddleofthemouth.Itoccursonlyinstressedsyllables./ə/isalsocalledaschwa.Itismadesimilarlyto/з:/,butwithlesstension./ə/isthemostfrequentlyusedvowelinEnglish.Both/ə:/and/ə/mayoccurinallthreewordpositions.Readingaloud–Payspecialattentiontothepronunciationoffrontvowelsandcentralvowels.ElectricCarsPeoplewereinterestedinmakingelectriccarsasearlyasthe1840s.Onesmallelectriccarwasmadethen,butitdidn’tworkwell.Then,in1912,GeneralMotorsproducedanelectrictruck.Theseelectricvehicleswereofcoursenotmadeforthepublictobuy.GeneralMotorswasthefirsttotryagaininthelastdecade.Itwasabigchallenge.Anelectriccarneedsabattery.Butthebatteriesareheavyanddon’tworkwell.Noneofthemcouldpoweracarfarenoughorlongenough.Andthenewtechnologycostalot.Theydidsucceedfinally.ThecartheybuiltwascalledtheEV1anditbecameavailableinCaliforniain1998.Itwasthefirstelectriccardesignedandsoldbyalargeautomobilecompany.Ex.Saythetonguetwisterandpayattentiontothevowels.BettyBotter'sBetterBatterBettyBotterhadsomebutter,But,shesaid,thisbutter'sbitter.IfIbakethisbitterbutter,Itwouldmakemybatterbitter.Butabitofbetterbutter,Thatwouldmakemybatterbetter.Sosheboughtabitofbutter–Betterthanherbitterbutter–Andshebakeditinherbatter;Andthebatterwasnotbitter.So'twasbetterBettyBotterBoughtabitofbetterbutter.