I programmed a n-back with words (text to speech) instead of piano sound or letter sounds. Yo only have to change spanish to english in the top menu. Here the link
http://competicionmental.appspot.com/tts3dnback .In the future i will make the app open source and add portuguese word. And i will check if the english word ar ok. Someone want to colaborate with checking if the list of 500 word are ok?
I think this program help to think in images, in two days i think a several seconds in images. is strange.
I am from Argentina. Sorry my poor English. Thanks!