Written communication can be literary or non-literary; therefore, a text either belongs to the fictional or the non-fictional text group. Especially within the non-fictional text-group the problem of classification is still open to discussion. Either one follows the concept that the major communicative functions of the language provide categories for useful distinctions; or one takes the position that 'the text types correlate with forms and ranges of human cognition' (Werlich, A Text Grammar of English, p. 21). According to the latter concept there are five basic text types:
description, narration, exposition, argumentation and instruction.
These are theoretical norms which in actual texts occur in manifold combinations and individual shapes (i.e. text forms).

1. Descriptive texts basically deal with factual phenomena, e.g. objects and people. Therfore you find many verbs of 'non-change' (e.g. to be, to stand, lie, sit etc.) and adverbs of place. Technical description tends to be neutral, exact and impersonal, while impressionistic description also gives expressions to the writer's feelings or moods.

2. Narrative texts types deal mainly with changes in time, i.e. with actions and events. Typical text type markers are verbs that denote 'change' as well as expressions of time (time-sequence signals)); but adverbs of place are not excluded. Narration is to be found in short stories, novels, biographies, anecdotes, diaries, news, stories and reports.

3. Expository texts tend to be explanatory: they explain objects and ideas in their interrelations. Typical verbs for the identification and explanation of objects and ideas are: to refer to, be defined, be called, consists of, contain etc. If a relation to previously mentioned facts and ideas is to be established, words like namely, incidentally, for example, in other words, etc. are used. A similarity to preceding phenomena can be expressed by similarly, also, too; additional information can be indicated by words like in addition, above all, on top of it all, etc. Typical of this text type are the expository essay, the definition, the summary and the interpretative piece.

4. Argumentative texts deal with problems and controversial ideas. Reasons for or against some topic are put forward. The ultimate aim is always to win the reader/audience round to the author's side. There is a dominantly dialectical text structure, and words like but, by contrast, however, yet, still, in any case, so, etc. are linguistic signals of a contrastive text structure. But the basis of any argumentative text form has to be provided by expository passages, by the explanation of facts, concepts, developments or processes. While COMMENT tends to be subjective in character, scientific argument seeks to be objective.

5. In instructive texts the writer tells the reader/audience what to do. The instructive text type is based on the action-demanding sentence. Commercial and political propaganda, directions, regulations, rules etc. are typical examples because they aim at influecing behaviour.