dlh₁gʰó-
“long, extended”long, extended
Root for length. Gives English "long", Latin longus, Greek dolikhós.
Discussion
*dlh₁gʰó- is the Proto-Indo-European root meaning "long, extended." The unusual initial cluster *dl- underwent different simplifications in the daughter languages, sometimes making cognates difficult to recognise at first glance.
In Germanic, the cluster simplified and the root underwent Grimm's Law (*gʰ > g > k in some environments), yielding Proto-Germanic *langaz, whence Old English lang/long and modern English "long." Related derivatives include "length," "linger," "longing," "belong," and "along." German lang and Dutch lang continue the same form.
Latin longus "long" (from *dlongʰos with loss of initial *d-) gave English "longitude," "elongate," "prolong," "oblong," and "lounge." The Latin form also shows that the initial *d- was dropped in Italic.
Greek δολιχός (dolikhós) "long" preserves the initial *d- that Latin and Germanic lost, appearing in English "dolichocephalic" (long-headed, a term from physical anthropology).
Sanskrit dīrghá- "long" shows the expected satem treatment and a different vowel grade. Old Church Slavonic dlŭgŭ "long" and Lithuanian ìlgas (with loss of *d-) round out the picture.
The root illustrates how a single PIE word can look radically different across branches due to cluster simplification and regular sound laws.
Notes
Source of "longitude", "linger", "lounge", "prolong"
Related Roots
English Words from *dlh₁gʰó-
These modern English words descend from this root. Each page traces the full journey from PIE to present-day English.