[Alfonso]

I can't be sure of the connotation of the term in English. In Spanish you can use jerga de abogados as Poli said, if it's got a not very good connotation. If you say lenguaje de abogados, lenguaje del derecho or lenguaje jurídico it's more respectful with the language itself.

Anyway, technically speaking, for linguistics, jerga hasn't got a negative connotation. But, who speaks technically?