With English lauguage training there needs to be vobabulary suited to the business needs.  There can also be a short grammar focus, but above all plenty of practice along with corrections and explanations.

There are different topics of conversation at different levels:

Beginners

Free Time
Daily tasks
Likes and Dislikes
Asking questions
Talking about a daily routine
Basic vocabulary General and for work
Family and friends

Intermediate
Opinions and Discussing Activities (General or for Work purposes)
Many varied areas of Conversation:
General life objectives
Working life
Travel
Places to live
Life choices and events

Advanced
Formal conversations
Business English specific to your needs
Problem solving - explaining suggestions, giving advice and instructions
Dealing with customers
Explaining  in some detail tasks and responsibilities

Pactise for phone calls in-company and to clients and responding correctly to emails