TITLE: Is mathematics the only language that is not subject of interpretation?
QUESTION [5 upvotes]: Do you know any other "language" that is used by people except mathematics and is not subject of interpretation? By subject of interpratation I mean e.g. that 1 000 000 people will undertand that 1 + 1 = 2 and never 3. E.g. when you say that "This flower is red". Some people will think that it is darker, some lighter etc.

REPLY [3 votes]: What is room for interpretation after all?
Statements are always subject to interpretation. 
To make sure there's no ambiguity in a statement you need to build a more or less complex system of axioms and corollaries that prove your statement true. The same can be applied to the flower you point at. If you state precisely which aspect of the flower you are talking about and what measure of color you apply then you can disambiguate such statement just in the same way. 
While it might not always be feasible to disambiguate anything it is not always necessary or desired either.
It is interesting that you came up with the example of constructivism. 
Indeed every person has different pictures in mind that are used to describe their sensory perceptions conceptually. 
This diversity is usually not a problem as there are a lot of norms and conventions "socialized" into each individual that disambiguate each others actions (including verbal utterings). Admittedly these are somewhat implicit and vary along the time and across subcultures but they provide the solid ground without which a society could not function.
As someone has mentioned computer programming to be free from interpretation, I would argue that. The programmer carefully makes explicit decisions about features and functionality, edge cases and error handling. But he usually starts with a problem statement, which he interprets. He then surrenders his code to some other application which again interprets it, and finally bring it to execution.
I would argue that the average programmer knows all of the default settings that are implicitly being used by the compiler, nor is he aware of the implications of all its "optimizations".
That is, the same dependency on mutually agreed conventions as in mathematics and in any other field here.
As for your example of $1+1=2$ there probably are millions of people that interpret this equation as you would expect. Such fact might be commonly accepted without any doubt, but as this question shows this is only true if the prerequisites are indeed defined accordingly. 
Therefore, a mathematician when being asked about the validity of $1+1=2$ should reply a fuzzy it depends, just as the attorney when being asked for legal advice would.