physical touch, quality time, acts of service, words of affirmation, gifts.
The book does a very good job of explaining the five and helping you to figure out what your own are (sometimes we don't even know) and those of your spouse.
it can be helpful in learning to recognize that even though your spouse doesn't express love in your way they may still be expressing love.
The hard part (as cemar pointed out) is getting the spouse to speak your language or heck just allowing you to speak your own once in a while.
