Q: The words “tree” and “true,” according to a TED video, have a common ancestor. From what I gather, this was back in prehistoric times, before there was writing. So how do we know the first thing about an ancient language if there’s no written record of it?
A: Historical linguists believe that “tree” and “true” have a common prehistoric ancestor, a belief that’s based on studies of a reconstructed, hypothetical ancient language known as Proto Indo-European (PIE for short), not on any written evidence.
By studying members of the present Indo-European family, linguists have extrapolated back to the presumed prehistoric language. The Indo-European family comprises many European and Asian languages, including English.
In reconstructing the PIE vocabulary, for example, linguists have used the comparative method, a technique for finding similar words in various Indo-European languages.
As the linguist and phonologist Calvert Watkins explains, similar words, or cognates, in present Indo-European languages “provide evidence for the shape of the prehistoric Indo-European word.”
Watkins, author of The American Heritage Dictionary of Indo-European Roots, says “tree” and “true” are ultimately derived from deru-, a Proto Indo-European root meaning to “be firm, solid, steadfast.”
This PIE root gave prehistoric Germanic the terms trewam (“tree”) and treuwithō (“truth”), and Old English the words trēow (“tree”) and trēowe (“true”), Watkins writes. (Old English spellings vary considerably.)
The earliest example of “tree” in the Oxford English Dictionary (with the plural treo) is from the Vespasian Psalter, an illuminated manuscript dated around 825:
“Muntas and alle hyllas, treo westemberu and alle cederbeamas” (“Mountains and all hills, fruit trees and all cedars”). We’ve expanded the citation, from Psalm 148.
And in Pastoral Care, King Alfred’s late ninth-century translation of a sixth-century work by Pope Gregory, an unbeliever is compared to a barren tree:
“Ælc triow man sceal ceorfan, þe gode wæstmas ne birð, & weorpan on fyr, & forbærnan” (“Every tree that does not bear good fruit shall be cut down and cast into the fire and burnt”). We’ve expanded the OED citation, which refers to Matthew 7:19. The dictionary describes triow here as a variant reading of treow.
When “true” showed up in Old English, it meant loyal, faithful, or trustworthy. Here’s an example from Beowulf, an epic poem that may have been written as early as 725:
“Þa gyt wæs hiera sib ætgædere, æghwylc oðrum trywe” (“The two were at peace together, true to each other”). Here trywe is a variant spelling of trēow.
As Old English gave way to Middle English in the 12th century, the word “true” came to mean accurate or factual, as in this example from Layamon’s Brut, an early Middle English poem written sometime before 1200:
“Belin ihærde sugge þurh summe sæg treowe of his broðer wifðinge” (“Belin heard it said through some true report of his brother’s marriage”). The passage refers to Belin and Brennes, brothers who vie in Anglo-Saxon legend to rule Britain.
And this example is from Wohunge Ure Lauerd (“The Wooing of Our Lord”), a Middle English homily written sometime before 1250. The author, presumably a woman, tells Jesus of her passionate love for him:
“A swete ihesu þu oppnes me þin herte for to cnawe witerliche and in to reden trewe luue lettres” (“Ah, sweet Jesus, you open your heart to me, so that I may know it inwardly, and read inside it true love letters”).