Summary: I have been thinking of chemicals as “language”.
We have been using chemical based communication for a long time.
We are simply not thinking about this acts in terms of communication.
When we input a chemical into our bodies (medicine for example) we are asking our bodies if it can perform a task similar to those of other bodies (in trials and experimentations.)
The body usually provides feedback in response (communication).
Chemicals are a type of information, in the same way that programs, codes, languages, are.
See related post: Multinformation.