Comparative linguistics, or comparative-historical linguistics (formerly comparative philology[1]) is a branch of historical linguistics that is concerned with comparing languages to establish their historical relatedness.
Raree studies have been done in my country regarding this topic.
There are many types of language comparison and they need not to be diachronic and the goal need not be to establish historical relatedness: from comparing all languages or a representative sample of the world's languages (typology) to comparing the languages of a specific language family (as Romance languages) or even comparing only two languages of the same language family or different families (sometimes this is refered to as contrastive linguistics).