Many techniques in software language engineering get their first validation by being prototyped to work on one particular language such as Java, Scala, Scheme, or ML, or a subset of such a language. Claims of their generalisability, as well as discussion on potential threats to their external validity, are often based on authors' ad hoc understanding of the world outside their usual comfort zone. To facilitate and simplify such discussions by providing a solid measurable ground, we propose a language called BabyCobol, which was specifically designed to contain features that turn processing legacy programming languages such as COBOL, FORTRAN, PL/I, REXX, CLIST, and 4GLs (fourth generation languages), into such a challenge. The language is minimal by design so that it can help to quickly find weaknesses in frameworks making them inapplicable to dealing with legacy software. However, applying new techniques of software language engineering and reverse engineering to such a small language will not be too tedious and overwhelming. BabyCobol was designed in collaboration with industrial compiler developers by systematically traversing features of several second, third and fourth generation languages to identify the core culprits in making development of compiler for legacy languages difficult.