Visual Latin: How to learn the words

I received this question recently:

My son is doing your visual Latin course and he is on lesson 13. When he translates the sentences and paragraphs there seems to be a lot of words that he has not learned yet. Should we look these up or are missing where they are being taught?

Here is my reply:

Each new word should appear in the vocabulary section of the lesson in which it first appears.  That said, I believe the best way to acquire new vocabulary in a language is via reading.  This is why I was not afraid to add new vocabulary to the course.  Though painful at first, students will eventually pick up more vocabulary via reading than they will via vocabulary lists and flashcards.

If your son has access to the internet (which, I know, can be a dangerous thing), have him keep Whitaker’s Words up.  Whenever he encounters a new, or difficult word, he can simply type the Latin word.  Immediately, he will have an accurate translation of the word.  Best of all, he can enter the word in any form.  He does not have to first identify the nominative case, as required in a dictionary.