First and foremost language is perceived as a communication medium.

As such it needs clarity and consistency, otherwise information could not have been reliably exchanged and or preserved through its use.

But language is used for many other purposes than for simply ‘translating’ raw data. Where to find a certain object or how to execute a certain task.
We use it to convey sentiment – the way we are affected by the raw data that has become known to us, and to communicate our particular understanding of things. Our point of view about what has happened around us.
Furthermore we use it to convince people. To do things or to accept our points of view.

All these different uses involve a considerable amount of negotiation.

Regarding immediate goals – the things we are negotiating about, but also some that is taking place ‘under the table’ and involves the continuous fine tuning of the instruments used during the negotiating process. The words themselves.

These negotiation instruments – the language itself, in fact, have to be constantly re-calibrated for two rather obvious reasons.
For starters, the reality around us – and our understanding of it – is changing constantly.
Secondly, every negotiation involves a degree of ‘shade’. In fact that ‘shade’ is exactly the space where ‘change’ happens, where the positions of the two negotiators overlap and where the two can swap ideas.
If words would be rigidly precise than we’d have to invent new ones every time reality changes, no matter how minutely. Also whenever our understanding about things deepens, no matter how shallowly.
Simultaneously, too much ‘linguistic precision’ would kill not only poetry and our ability to convey our real feelings to other human beings but would also gravely impair our ability to influence each-other. Could you imagine how our life would be if a polite intervention would sound exactly like an SMS message of if a marriage proposal would be similar a requisition order?

More about how the linguistically mediated interplay between us has brought about our own self-awareness can be found here:

Humberto Maturana, The Origin and Conservation of Self-consciousness.