How Do You Pronounce Cthulhu?

The pronunciation on this office's file is Khlul'-hloo: the first syllable thick and guttural, the vowel as in "full", the second syllable a breathy "hloo". That is the form Lovecraft gave in a letter of 1934, where he added that the sound could only be approximated by any human voice, and by any human spelling.

The renderings correspondents arrive with are commoner and softer: "kuh-THOO-loo" and "kuh-LOO-loo" are both heard, and this office has no ruling against either. The name comes into the record as a sound written down by witnesses who could not agree on how to write it.

The chant

The cult's own chant is on file in The Call of Cthulhu, among the prisoners taken at the swamp rite in Louisiana in 1907: Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn. The sense given at the inquiry was that in his house at R'lyeh, dead Cthulhu waits dreaming. R'lyeh is filed UNCHARTED, and its coordinates on record are given in the Dispatch listed below.

Other names worth settling

Since the question is rarely asked in isolation: Yog-Sothoth is pronounced as it is written, in three syllables on the first and last, and Nyarlathotep with the stress on the second syllable. The Archive carries no ruling on R'lyeh, which the witnesses wrote down as they heard it.