Research group UVAL (Unitat de Variació Lingüística – Language Variation Unit) studies: a) linguistic variation (both within the group and in the individual) and linguistic change, as inherent phenomena to natural language, and b) as well as their effects on our understanding of different linguistic dimensions and their implications for improving the design of linguistic applications. This variable nature of human language affects all linguistic levels as well as the rules governing linguistic behaviour and communicative interaction. UVAL studies three dimensions of linguistic variation:

• Language variation within the group, which deals with sociolinguistic variation and language change, drawing from Labov’s Theory of Variation and Language Change, by means of the correlation between internal (linguistic) and external (social, stylistic, and pragmatic) factors, which affect language behaviour in multilingual sociolinguistic situations and in situations of language contact, and through the observation of the direction of language change by analysing variation both in apparent and real time.
• Variation within the individual, drawing from the individual’s idiolect, which supplies useful data for the development of the different areas of study in which forensic linguistics is structured; such discipline deals with all the aspects related to the interface between language and law, taking into account that a) there is more inter-speaker/writer variation than intra-speaker/writer; b) an individual’s idiolect keeps quite constant in all genders and registers; and c) it does not change too much throughout time, so that it is possible to calculate an Index of Idiolect Similitude ISI) in all linguistic levels (phonological, morpho-syntactic, semantic, pragmatic, discoursal).
• Sociodemography of language: uses, attitudes and demolinguistic projections, a macrolinguistic dimension of variation, which deals with social/demographic aspects of competence/use and of language varieties in order to be able to understand the reason why individuals decide, at a specific moment in their life, to language shift, and proposes in the framework of demo-linguistic models to evaluate language planning using a predictive scheme and applying demo-linguistic projections.

Since 2001, UVAL is a consolidate research group in the Pla de Recerca de Catalunya (SGR2001 and SGR2005). Between 1995 and 2000, UVAL researchers belonged to LATRAL (Lingüística Aplicada al Tractament del Llenguatge – Linguistics Applied to Language Processing), also a consolidate research group Pla de Recerca de Catalunya (1995SGR00042, 1996SGR00045, 1998SGR00085, 2000SGR00085).