Communication is mostly vocabulary.  Being able to say and understand "men 2 talk the table at together" is fluent.  The grammar is weak but the meaning will be understood.

Building at least a high school level vocabulary is vital.

We fully embrace the Oxford 3000 Learner's dictionary.   English experts at Oxford have chosen approximately 3,300 words which comprise a native English speaker high school level vocabulary.  We help you review the words you know, master new words, and demonstrate you have learned.

We will help you master a university level vocabulary if you care to.