I had that happen to me w/ the German tapes. An NLP practice would be to just slow the words down mentally to the point of dropping off to sleep. By the time you get to the end of a phrase, you'll be sound asleep
If you are seeing images, then slow the images down to the point of dropping off to sleep.
Make up an affirmation of your choice to speak to your condition. Eg., I value learning Spanish and accept a wonderful sleep during the night.
