vocabulary profiling

Knowing the most commonly used words helps us to teach English more easily.  Generally, in textbooks the language is simple, writers use most commonly used words to make the meaning clear.  Learning common words helps students to communicate with others because everybody can understand most commonly used words.  Students can learn most commonly used words in their daily lifes but teaching them for these words will help them.  I think dictionaries are not enough sometimes.  Suppose we have a context that include unknown words we want to look for meanings but when we look at dictionaries we can confused about in what content were thet used.  So if teachers create students wordlist according to their text, it will be very educational.  Students will learn more words.