Linguists are sometimes confronted with choices concerning language names. For example, one and the same language may be referred to as Persian or Farsi. This short paper discusses some principles that one might use for making decisions when there are variant forms in use, or when one feels that none of the existing names is appropriate. The principles discussed here arose from work on Glottolog, an English-language database of the world's languages (Glottolog.org), where each language has a single primary English name (though variant forms are of course included), and where the goal is to choose the best variant form as the primary name of the language. Whenever the question arises which variant name form to choose, the Glottolog editors are guided by these principles, so they are formulated in a prescriptive way, but with explanation and justification for each principle. It seems that the general issue is also quite important for language documenters, because the names of non-major languages are often not fully established yet, and naming decisions have to be made.