I read a book to learn new words.

[Maybo]

Are the following sentences correct?

1. I read a book to learn new words.
2. I read a book to learn new vocabulary.
3. I read a book to learn new vocabulary words.

 

[tedmc]

You read books to learn new words to improve your vocabulary.

 

[5jj]

The first two are OK. The third is not.

 

[emsr2d2]

Out of curiosity, were you thinking of "read" as present simple or past simple?

 

[Maybo]

Out of curiosity, were you thinking of "read" as present simple or past simple?

past simple

 

[tedmc]

I prefer to write "to learn new words". You learn new words to build up your vocabulary (body of words).
Words are a subset of vocabulary.