Top 100 words in a language

In TPRS, we focus heavily on the words that are most often used in communicative language. There is a frequency dictionary for the Spanish language. Blaine Ray tells us that if he had it his way, he would design the curriculum around the 100 most frequently used words in a language, and once those were acquired, he would go on eventually to the 1000 most used words. Of course, he does throw in the silly and unexpected words too, like blue cockroach and flying elephant. These words are mostly to keep interest high - I tell my students the crazy stuff is mental super glue - they make the rest of the words stick in our minds.

The first time I read through the frequency list for Spanish, I was shocked at how many of these words that are used daily are not found in our textbooks. Some, like algo (something) are found in upper level classes. And many are just too common to omit, like el (the). Still, I am wondering how far down the word itinerary is, and why oh why I have to teach it as if it were vital to communication. Most of my students don't even know what an itinerary is in English!