I have examined Spanish textbooks used over the past two-hundred years and have noted how their authors were pragmatically or culturally motivated. Not surprisingly, the various methods they claim to use respond to wider societal issues and values. After all, textbooks are products that have to sell.
In the USA's early days, a perky desire for establishing commerce with our newly liberated neighbors to the south seemed to prevail, appealing to Yankee pragmatism and its mercantile spirit. Later, the value of foreign languages was more an expression of upper class aspirations of a growing middle class who aspired to imitate the leisure class and send their children on the Grand Tour of Europe. Hence, cultural advantages were cited in the preface to many textbooks.
As I have examined textbooks produced over the past two centuries, I have found amusing and enthusiastic declarations of loyalty to the Direct Method in one text, to the Natural Method in another (often treating previous methods or other methods as obsolete, unenlightened and so forth). Late in the nineteenth century, it dawned on someone to glean from all previous "methods" and inject some sense into at least the rhetoric of pedagogy and advertising and baptize his book as the culmination of much labor to create the Eclectic Method.
The fact is, when an effective teacher is in front of one student, the goal is to try to find out what learning strategies work best for that person -- and damn what it is called. A good teacher has a bag of tricks and knows how to explain the same concept in many ways. However, when a teacher is in front of a crowd of students, as is most often the case in current schools from kindergarten through college, it is difficult, if not impossible, to find one method that will work for all students, every day. Using every trick for every concept would make for a very long day indeed -- a fact that goes a long way to explain why so many people are frustrated with the education establishment, other issues aside.
In the late 1960s, a wonderful book was published, entitled 25 Centuries of Language Teaching
Over the decades that followed, I also observed the explosion of a "new" field: the second-language acquisition expert. As I have listened to many newly minted Ph.D.s effusively endorsing this or that method or text, accompanied by more supplemental materials and programs than I could ever use, I have become concerned that consumerism has eclipsed pedagogy, that too many gadgets and clicks of a mouse now stand between a learner's mind and the object of study. Sometimes, perhaps most of the time, it is important to unplug and confront the material, instead of engaging with the media through which one is trying to learn. I have sometimes learned a new trick from one of these experts, but every time, returning to 25 Centuries of Language Learning, I have found that the method has been tried before. Using modern technologies to deliver what is, in the final analysis, tried-and-true methods, gives the illusion of novelty. As the great Jesuit wit Baltasar Gracián observed in the 1650s: Novelty is bewitching.
Ultimately, the best foreign language textbooks and software programs are eclectic -- not in an abstract sense for public relations and advertising, but in a true sense, in terms of their balance of activities to appeal to different learning styles as evenly as possible. They include a good mix of activities that appeal to different styles of learning in order to not -- please excuse the phrase -- leave anyone behind for very long. See the sidebar on my blog for links to hundreds of free mini-lessons I've written for Spanish students and teachers.