Vocabulary has a starring role in language learning. On the one hand, it is the absolute essential to know, and, on the other hand, if you know enough words you will not need to know so much grammar.

In the 1980s I picked up a travel book titled Never Make a Reservation In Your Own Name, by Leonard S. Bernstein. The first chapter made a lasting impression on me. It’s called “Thirty Days to Learning Italian,” and Mr. Bernstein’s not kidding. He tries to learn rapidly a little of the language before visiting any country; in this case it was Italy. He spends about a month studying by himself from a book, then hires a college student for conversation in the time remaining before his trip. When he arrives, he looks for opportunities to use his (bad) Italian. Mr. Bernstein maintains that “half the trick of learning a language is learning what not to learn,” so he treats the verbs very lightly.

But he does learn vocabulary. He says, “The cornerstone of understanding language is building a basic vocabulary.” If you know the word for what you want, you’ll succeed in communicating.

Maybe you discover you have no towels in your hotel room. It can be amusing to find the

housekeeper and pantomime drying off after a shower. But it’s much easier to pick up the phone and say, “Quisiera una toalla, por favor.”

Meet my friend Benjamin.

He was once robbed in a Central American country. In telling the story to his friends, he said, “ There was nothing I could do. They had a cuchara.” His friends burst out laughing. Why hadn’t he been able to defend himself against robbers wielding a spoon? Now a knife…a cuchillo…that would have been a different story.