X defines types of language functions in academic texts, including definition, description, and classification. Definition defines terms using words like "is", "is called", and "may be defined as". Description provides details about position, structure, composition, size, shape, function, and properties. Classification categorizes types of X based on certain criteria. Instructions provide directives for actions related to X using words like "do", "don't", "should", and "shouldn't".

1. Funciones del lenguaje
en textos académicos

2. Definición
X is ...
X is called ...
X is known as ...
X may be defined as ...
X is a type of Y that/which ...
A type of Y which ... is X

3. Descripción
Posición: A is parallel to B.
Estructura: X is linked to Y by Z./
X includes Y & Z.
Composición: X is made of …
Tamaño/Peso: X is 6mm. long.
Forma: X is rectangular in shape.
Function: X is used for … ing.
Propiedades: X is malleable.
Proceso: Xis heated to its melting point.

4. Clasificación
There are … types of X: Y and Z.
X may be classified on the basis of
Y., etc.

5. Instrucciones
Do …
Don’t …
You should do …
You shouldn’t do …