▁instruction . ▁It ▁soon ▁became ▁a ▁second ▁leg ▁of ▁his ▁business , ▁as ▁on - site ▁learning ▁was ▁pa ired ▁with ▁development ▁of ▁self - learning ▁correspond ence ▁courses ▁and ▁production ▁of ▁related ▁aid ▁materials . ▁They ▁consisted ▁of ▁two ▁types . ▁One ▁was ▁own ▁text books ; ▁they ▁contained ▁ex cer pts ▁from ▁literary ▁works , ▁though ▁also ▁phr ases ▁tail ored ▁for ▁daily ▁usage . ▁Another ▁one ▁was ▁record ings . ▁Initial ly ▁ph on ograph - int ended ▁cyl ind ers ▁were ▁used ; ▁first ▁brand ed ▁by ▁Cort ina , ▁after ▁ 1 8 9 6 ▁they ▁were ▁made ▁by ▁Ed ison ' s ▁National ▁Ph on ographic ▁Company . ▁In ▁ 1 9 0 8 ▁he ▁registered ▁the ▁tra dem ark ▁of ▁Cort in aph one , ▁s elling ▁own ▁brand ▁of ▁ph on ograph , ▁and ▁since ▁ 1 9 1 3 ▁his ▁company ▁started ▁to ▁issue ▁flat ▁round ▁record ings . ▁The ▁Cort ina ▁school ▁kept ▁using ▁English ▁for ▁instruction ▁until ▁ 1 9 2 0 , ▁when ▁they ▁switched ▁to ▁target ▁language ▁only . ▁Ar ound ▁ 1 9 2 0 ▁he ▁was ▁market ing ▁" C ort ina ▁ph on ograph ▁out fit ", ▁advert ised ▁as ▁more ▁efficient ▁than ▁teaching ▁by ▁instruct ors . ▁ ▁Cort ina ' s ▁language ▁business ▁proved ▁rather ▁successful . ▁His ▁method ▁of ▁teaching ▁was ▁awarded ▁corpor ate ▁pri zes ; ▁the ▁school ▁– ▁since ▁ 1 8 9 9 ▁named ▁Cort ina ▁Academy ▁of ▁L anguages ▁-