Some language-particular terms are comparative concepts

Haspelmath (2010) draws a categorial distinction between language-particular terms - terms used in the description of specific languages - and comparative concepts - terms used for crosslinguistic comparison. This seems like a valid distinction for a lot of terminology, but it is also true that there are "portable" terms that are suitable both for the description of specific languages and for crosslinguistic comparison. This descriptive metalanguage is analogous to the descriptive vocabulary employed in other observational sciences, and its elaboration is an important enterprise for both descriptivist and comparative linguists.