Communicative Role

"Samuel F.B.Morse one of the inventors of the electric telegraph believed he had discovered a practical way of using [electromagnetism] as a means of communication and interchange of thought in written language, irrespective of distance and time save that required for manipulation, and that it would ultimately become a daily instrumentality in domestic as well as public life." from the Victorian Internet written by Tom Standage.

All language training classes have different objectives. whether for business or just conversation, travel abroad or professional training all undergo a primitive goal and that's communication.
Designing a communicative class in a language lab requires thoughtful considerations.
One can attempt in piling the lesson plan with too many activities that by the end of the class it is just a paper and pen task centered individually rather than having any communication in groups.
As an ESOL teacher for quite many years I have found that the more prepared you are knowing your students the better you can develop lesson plans designed for that specific students even in a multi-level or multi-cultured and what's more multi task oriented classes!
Just recently in my Distance learning ( Online ) classes of language training we had introductory classes of getting to know each other and defining our goals of learning the desired language.
The outcome was lessons specifically designed for that group of students meeting their needs with communicative needs.
Examples of this was removing any Translation activity from the lesson plans and getting students more involved in conveying their thought into TL ( Target Language ) within their limit.
Another example was omitting any One language task activity. That is all the activities were circled around the communication into two languages. Rather than just having " write the meaning of these words in your own language" we asked the students to come up with their own sentences or phrases at the time of need of an exemplified situation.
This is not to say that we are going to remove all that has done so far in learning a language but the farther we see the use of language in the international arena proves how important it is to transfer one's message into communicating with others.