Each constituents of a sentence always signal both a grammatical relation (e.g., that of representing the subject) and a semantic/pragmatic relation (i.e., that of referring to an entity of the world). The paper argues that this double function does not pose any particular problems only when analyzing isolated, complete and a-contextual sentences, and discusses the problems posed to the received notion of subject t by the more or less indexical nature of the units corresponding to the (explicit or implicit) subjects of contextualized sentences from a text. In these cases, the difficulties of students, teachers and textbooks in explicitly distinguishing the expression of the subject from the name of its referent are particularly evident, especially when the subject corresponds to a zero (Ø) pronoun, as is frequently the case in Italian. Our data show, however, that the same difficulties can appear with more explicit subjects as well. This widespread confusion between subject and referent is often disclosed by the “notional” or ad sensum identifications of subjects made by students for different types of sentences (e.g., when they correctly identify an explicit subject of a sentence but use a contextual synonym to name or to say it), but it is always potentially lurking in all those general definitions of subject and textbook exemplifications which do not take into proper account the role of discourse and information dynamics in sentence structurin
