Teaching English as a Foreign Language, Second Edition

The transmission of information
As the major and most complex technique we have of
communicating information, spoken language allows us to
produce a sequence of vocal sounds in such a way that
another person can reconstruct from those sounds a useful
approximation to our original meaning. In very simple terms,
the sender starts with a thought and puts it into language.
The receiver perceives the language and thus understands the
thought.
 
The sender has to encode his thought, while the receiver
decodes the language. Most of the time, these processes are
so fast that one could say that both sender and receiver
perform them instantaneously and virtually simultaneously.
When thoughts are very complex, the process takes longer.
Likewise, when an unfamiliar language, or dialect, is being
used, the process is slow enough for the distinction between
thought and language to be quite clearly observed.
Language and thought
The best way to regard the relationship is to say that
‘language is a tool in the way an arm with its hand is a tool,
something to work with like any other tool and at the same
time