Acts of speech, verbal behavior, can be studied as objects of a natural science as the behavior corresponds to real organic processes. Language, however, cannot be studied as a natural science; language and all the hypothetical elements of language are mere perceptual abstractions and do not correspond to anything material; language and its elements lack mass and energy and can therefore not be studied as real objects. Language practices can only be described, interpreted in words. - I propose to include linguistics into a broader study of expressions and interpretations with a clear differentiation between (i) the biological abilities to express and interpret, and (ii) the social practices which constitute human language. Further this entails that both in relation to the social sphere and the biological we have to study, not language, but expressions, that is, study the biology of how expressions are organically produced and the social practices of expression. By thus calling for a study of expressions and interpretations instead of a study of the more narrow fields of speech and language another crucial implication follows. This is the necessity to admit into the realm of the study the whole act of bodily expressions and not only the alphabetical symbols by which we in abstraction depict the perceptions we form merely on the sound-patterns in exclusion of all the other aspects of the speech act.