The "Indo-European Family"

The other day, I wrote:

For at least fifteen years now, I've taken an interest in the Indo-European family and the relationship between older languages. Sometimes, this is just for curiosity's sake. Sometimes, it helps me better understand modern languages.

Typically, when you’re given a list of Indo-European cognates, the name of the game is to show the obvious interrelation between the languages with transparently similar words. Today, I’d like to take a different tack, showing where different words come from and how an understanding of the Indo-European background can offer better understanding and help you make connections you might otherwise miss. The topic is family vocabulary; the languages we’re looking at are Irish, Italian and Dari. To make the connections for Italian and Irish, I’ll be going by way of Latin and Old Irish. I don’t happen to know anything about Avestan, Old Persian, etc, so we’ll have to make some logical leaps on the Dari.

Father
Proto-Indo-European pəter > Latin pater > Italian padre (note that the “ə” denotes a laryngeal, i.e. a sound in the throat that developed into a vowel later)
PIE pəter > Old Irish athair > athair (initial “p” in PIE and proto-Celtic dropped by the time of Classical Old Irish)
PIE pəter > Dari padar

Mother
PIE mater > Lt. mater > It. madre (works just the same as pəter)
PIE mater > Oir. máthair > Ir. máthair (same)
PIE mater > Dari madar

Mother and father are pretty easy. There’s a third word in the same family:

Brother
PIE bhrater > Lt. frater > It. fratello (diminuitive suffix to mark a little “frater”)
PIE bhrater > OIr. derb (certain) + bratháir > derbh-bhratháir > Ir. deartháir (imagine if in English we said “dear brother” so often that we started running it together as “dearother” and you can sort of see what happened.)
PIE bhrater > Dari bradar

The next word has a rather different base form, but notice how Italian and Irish make the same transformations to it as with brother:

Sister
PIE swesor > Lt. soror > It. sorella
PIE swesor > OIr. derb (certain) + siur > derb-ṡiur > Ir. deirfiúr
PIE swesor > Dari khahar (cf. Middle Iranian khwahar, with PIE s > h/kh; this also happens with Greek, hence Grk. helios, Lt. sol as in solar)

Our last two words teach us a different lesson, namely that even when modern Indo-European languages diverge in vocabulary, knowing the background of the words can help us make new connections.

Son
PIE dhei- (to suckle) > Lt. filius > It. figlio (think of filial devotion)
PIE maghu (youngster) > OIr. macc > Ir. mac (maghu is also the source of maiden)
The Dari is pisar, cf. Farsi pesar, Lat. pes, Grk. paidos; not sure of the PIE root

Daughter
PIE dhei- (to suckle) > Lt. filia > It. figlia (feminine of figlio)
Proto-Celtic eni-gena > OIr. ingen > Ir. iníon (presumably, a daughter is “born into” a clan)
PIE dhugeter > Dari dukhtar (that one was pretty easy!)

Obviously, you wouldn’t want to do this kind of research with every word you ever intend to learn! On the other hand, trying to come up with a mnemonic for every word can get pretty tedious too. The important thing is to find devices for better remembering and understanding what you learn so that it will stay with you. And sometimes etymology is just what you need to make a connection (a real connection!) that you might have missed. This is especially the case if you use it often, as you will start to develop an intuition for connections between languages and language families so that as you learn new words, they come alive on the basis of old patterns you’ve already figured out.

By the way, if you suspect a relationship between an English word and a word from another Indo-European language, a great place for etymologies is etymonline.