Style guides or writing recommendations play an important role in the field of technical documentation production, e.g. in industrial contexts. Also, writing recommendations are used in technical contexts together with machine translation (MT) in order to circumvent the MT system's weaknesses. This paper describes the evaluation and adaptation of a language checker deployed in the project int.unity In this project, both MT and a specialised language checker were adapted to the requirements of non-expert users and a non-technical domain. The language technology was integrated with the groupware platform BSCW to support the multi-lingual communication of geographically distributed teams concerned with trade union work. The users' languages were either German or English, i.e. the users were monolingual. We chose linguatec's server version of Personal Translator 2004 MT system for the German<->English translations. The language checker CLAT for German and English has been developed at IAI. It is used by technical authors to support the production of high-quality technical documentation. The CLAT core system was adapted and extended in order to match the new requirements imposed by both the user profile and the subsequent MT application. In this paper, the focus will be on the assessment and adaptation of style rules for German.