In the 1700s it was clear to European scholars that certain languages were related to each other. French ciel, Spanish and Italian cielo, and Portuguese céu were clearly versions of the same thing, and had obviously descended from Latin caelum. It was also apparent that there were relationships between languages that hadn’t descended from Latin but were similar to each other: English earth, Dutch aarde, and German Erde were too close to be a product of mere coincidence. But it wasn’t until 1786 that people started to consider that all of these languages might be related to each other on a deeper level.

That’s when Sir William Jones, a British language scholar and judge who had been posted to Calcutta, suggested in a speech to the Asiatic Society that the classical Indian language Sanskrit had such strong similarities to classical Latin and Greek that

no philologer could examine them all three, without believing them to have sprung from some common source, which, perhaps, no longer exists; there is a similar reason, though not quite so forcible, for supposing that both the Gothic and the Celtic, though blended with a very different idiom, had the same origin with the Sanskrit; and the old Persian might be added to the same family.

The similarities could be seen when comparing Sanskrit to various Latin and Greek words, but they were most striking when all three languages overlapped, as they did for the word father:

Sanskrit Latin Greek
pitar pater pater

 

When laid out this way, tantalizing similarities to other European languages came into focus:

Sanskrit Latin Greek Old English Old Norse German
pitar pater pater faeder fathir Vater

 

The words for father in these very different and geographically distant languages seem close enough, but it could be by chance. Could a p sound really have transformed into an f sound (the German V is pronounced as f)?

Philologists started looking for explanations that would shed light on the sensed kinship between these forms. The person who finally found a satisfactory answer was Jakob Grimm of the Brothers Grimm, who was well-versed in the history of Germanic languages from his work digging through old folktales. He formulated what is now known as Grimm’s Law, the first of many sound-change laws that were the foundation of the evidence-based, scientific study of linguistic history that would dominate the following century.

The first part of Grimm’s law says that in the Germanic languages, the p of proto-Indo-European—the hypothetical ancestor of Sanskrit, Latin, Greek, and many other European and Indian languages—turned to f. Bolstering his case was the fact that a whole other group of words showed the same alternation as father, including foot, field, and fill.

Sanskrit Latin Greek Old English Old Norse German
pat ped- pod- fot fotus Fuss
prthu (broad) planus (flat) platus (flat) feald fold Feld
prnati pleo pleroo fyllan fylla füllen

The similarities may not be as striking for these words as they are for father, but when this p to f correspondence (as well as other correspondences) showed up across hundreds of words, the argument for a common linguistic ancestor grew stronger and stronger.

Father/pater/pitar was an elegant, tidy example that helped facilitate our understanding of the development of the Indo-European family tree. Tell your dad all about it this Pitar's/Pater's/Father's Day!