(1)Theshiftfromsilenttosoundfilmattheendofthe1920smarks,sofar,themostimportanttransformationinmotionpicturehistory.(2)Despiteallthehighlyvisibletechnologicaldevelopmentsintheatricalandhomedeliveryofthemovingimagethathaveoccurredoverthedecadessincethen,nosingleinnovationhascomeclosetobeingregardedasasimilarkindofwatershed.(3)Innearlyeverylanguage,howeverthewordsarephrased,themostbasicdivisionincinemahistoryliesbetweenfilmsthataremuteandfilmsthatspeak.