During the last decade several constraint acqui- sition systems have been proposed for assisting non-expert users in building constraint programming models. GENACQ is an algorithm based on generalization queries that can be plugged into many constraint acquisition systems. However, generalization queries require the aggregation of variables into types which is not always a simple task for non-expert users. In this paper, we propose a new algorithm that is able to learn types during the constraint acquisition process. The idea is to infer potential types by analyzing the structure of the current constraint network and to use the extracted types to ask generalization queries. Our approach gives good results although no knowledge on the types is provided.