\vspace{-1.6cm} The paper studies the relations between ϕ-divergences and fundamental concepts of decision theory such as sufficiency, Bayes sufficiency, and LeCam's deficiency. A new and considerably simplified approach is given to the spectral representation of ϕ-divergences already established in Österreicher and Feldman \cite{OestFeld} under restrictive conditions and in Liese and Vajda \cite{LiV06}, \cite{LiV08} in the general form. The simplification is achieved by a new integral representation of convex functions in terms of elementary convex functions which are strictly convex at one point only. Bayes sufficiency is characterized with the help of a binary model that consists of the joint distribution and the product of the marginal distributions of the observation and the parameter, respectively. LeCam's deficiency is expressed in terms of ϕ-divergences where ϕ belongs to a class of convex functions whose curvature measures are finite and satisfy a normalization condition.
The structuralistic point of view seems to be applicable in the sociolinguistics as far as the relation of language norms and varieties is concerned. Language norms can be classifiable as components of human consciousness, the function of which is to regulate language expectations and actions. These norms reflect social and language phenomena. Varieties are coherent collections of language elements which can be distributed according to geographic, social or functional criteria. The relation between norms and varieties is that between invariant and variant elements. These units facilitate to operationalize the sociolin-guistic perception of language-users. Invariant constructs with their sociolinguistic relevance (segments of norms) are realizable in various ways, which depends on various factors determining communicative situations. The author suggests to coin the term normeme for the realizable unit and allonorme for the realized variants (segments of varieties).