As for the concept of ‘language’ presupposed on these pages, it comprises natural human languages whose primary medium of expression is sound. Gesture and touch languages are natural languages, too, but partly different from languages using sound.
The description of a language can be comprehensive, but it cannot be complete. It is necessarily incomplete if the language is extinct, because then information on many aspects not so far documented is forever unavailable. If it is a living language, it is an activity which is renewed every day. It generates new constructions and lexical items, new semantic and phonological variants; and traditional ones become obsolete. Thus, while a description may be more or less complete, it can never be exhaustive.
The presentation of a language is comprehensive to the extent that it treats all of its main aspects. In order to achieve this, it is organized at three methodological levels such that material of a given level is the object of the treatment of the next higher level. This organization may be visualized as follows:
| Level 3: | Comment on description | |
| History of research | Setting of present description | |
| Level 2: | Description | |
| System of language | Setting of language | |
| Level 1: | Documentation | |
| Discourse – Texts | ||
Level 1 encompasses a documention of the language in the form of data of discourse and texts, recorded and linguistically processed to a certain degree. They are transcribed, possibly edited, annotated and translated. Such data are a necessary part of the comprehensive presentation of a language. This is also the reason why the comprehensive account of a language is called a presentation rather than a description: Data are presented at level 1, but described at level 2.
Level 2 comprises the description of the language, including crucially a description of the data presented at level 1. It divides into two parts according to the object of description: On the one hand, the language as a semiotic system, on the other, the language as a historical object.
Level 3 bears, again, a meta-relation to level 2, as it comments both on the present description and situates it in the history of research.
The comprehensive presentation of a language thus defined is occasionally called a grammar of the language.1 The grammar of a language is the regular part of its system (consisting of morphology and syntax) and the linguistic description of it, thus part of the orange section of the above diagram.
1 E.g. in the series Mouton Grammar Library by de Gruyter Brill and the series Comprehensive Grammar Library by Language Science Press.