Some signs stand for themselves. Example: the `word’ for tongue in American Sign Language is the gesture of pointing to the tongue.
Q: Is this possible? Is it not the case that this is not a word at all, but a suggestion that one consider the indicated item? If I point at the sun, is my action identical with saying the word `sun’? Is it coherent at all for something to be a sign if the signified is the sign? Must it not refer elsewhere? Does a sign labelled `this is a sign’ tell us more than a sign shaped piece of wood?

To be a word requires a certain context. Example: the shape `spinach’ formed randomly in the clouds does not constitute the word `spinach’. Putting a can on a piece of paper with `spinach’ written on it, by contrast, does instantiate a communicative act. So the can of spinach becomes part of the symbol for itself.
Q: What if the can contains beans? Why does the symbol `spinach’ combined with the can indicate only the can and not the can + paper complex?

The `you’ in `would you please go?’ is anaphoric: it applies to whoever is being addressed in the same way that pointing a finger at the addressee functions in ASL. It is not indexical. It is a `sign for itself’; a part of the environment – the interlocutor – is used to refer to itself.
Q: Why isn’t it still an indexical?
Everyone may have their own version of a particular concept because everyone has different experiences. This is recognised by the introduction of the term `unicept’.
There are no indexical or demonstrative thoughts because indexicals and demonstratives involve self-signs and there can be no external objects in the mind.
See Also:
Husserl’s Phenomenological Reduction: What Is It And Why Does Husserl Believe It To Be Necessary?
Does Heidegger Establish That The Ready-to-hand Enjoys ‘Priority’ Over The Present-at-hand?