Repeat and review.
The old adage, “Use it or Lose it” applies here.
Review workbook pages by talking through them: talk about what the weather was like when you did that page, or what day it was, or what you ate for dinner. Recalling the learning situation often helps the child to recall the lesson.
Make a habit of using Spanish once a day, even for a few seconds. Perhaps when you get ready for dinner, you practice with por favor (please) and gracias (thank you). Your child can name colors of and count the plastic cups as you set them out on the table.
Use Flashcards: Cut the ones from the back of the book, but make your own as well. Even after your student has mastered the words, add them back in to the pile.
Use other books! When a child sees the words he has learned in another venue, they become more meaningful to him. These three of Sandra Boynton's line of Spanish Board Books are WONDERFUL additions to your Spanish Library at home: