Vocabulary words are the first priority in learning a second language. If you make a grammar mistake – people may still understand you, choose a wrong word – the chances of misunderstandings are very high.
Go it alone - English Phrase
How to use Today's Phrase
Most Commonly Confused Words in English (Letter ‘C’)
Most Commonly Confused Words in English (Letter 'B')
Commonly confused English words beginning with A by Liam Lusk