Abstract : This paper shows how large-coverage morphological and syntactic NLP lexicons can be developed by interpreting, converting to a common format and merging existing lexical resources. Applied on Spanish, this allowed us to build a morphological and syntactic lexicon, the Leffe. It relies on the Alexina framework, originally developed together 200with the French lexicon Lefff. We describe how the input resources --two morphological and two syntactic lexicons -- were converted into Alexina lexicons and merged. A preliminary evaluation shows that merging different sources of lexical information is indeed a good approach to improve the development speed, the coverage and the precision of linguistic resources.