Thousands of sacred chants were also transcribed into Western notation in the late-19th and early-20th centuries, although preservationists had difficulty deciphering the pneumatic notation of ancient manuscripts: often just a few squiggles or symbols to elaborate on a melody that it was assumed the singer already knew. Modality and untempered tuning, which result in the striking dissonances and harmonies of Georgian traditional singing, are ill suited for Western five-line notation. Improvisation, also a vital skill until the mid-19th century in Western classical music, is an integral element of both folk and sacred music in Georgia and further complicates transcription.

There are reverberations of the late-19th-century nationalist rhetoric today in Georgia, Mr. Graham said. But that early revivalist movement was quashed when, after a fleeting independence, Georgia became part of the Soviet empire in 1921. Georgia’s polyphonic folk tradition fared better than sacred music during that period, but the Soviets professionalized folk music and encouraged arrangements for large choirs, often at the expense of authenticity.

The debate over period practice in Western classical music also exists in Georgia. The Ensemble Basiani improvises and tunes its songs in traditional ways, replicating the performance styles heard on old recordings. As the choir of the Patriarchate in the imposing new Holy Trinity Cathedral in Tbilisi, however, the choristers sing in a more Westernized classical style.

The ensemble’s Mostly Mozart programs include folk music from eastern Georgia, in which two melismatic voices sing over a moving drone bass, and complex contrapuntal works from Guria, in western Georgia. There are songs for work, weddings, births, funerals, healing, drinking and feasts. “A Georgian is born and buried with a song,” as one 20th-century scholar put it.

The unexpected modulations and primeval yodeling of the earthy Gurian songs are startling. During a recent rehearsal in Tbilisi, the Ensemble Basiani practiced a traditional Gurian piece, a wild, multilayered, partially improvised song during which one singer yodeled with enthusiastic abandon. Afterward a choir member asked a listener, “Do you have a headache yet?” The Swiss-French composer Arthur Honegger, who died in 1955, is said to have failed in his attempt to notate a complex Gurian song.

In addition to the concert stage, a visitor to Georgia is most likely to hear folk songs at a supra, a multicourse feast with locally produced wine and Georgian delicacies like khinkali (dumplings) and shashlik. A tamada (toastmaster) encourages heartfelt toasts to women, wine, friendship and the motherland. During a recent supra in Signaghi, a hilltop fortress town with sweeping views of the Caucasus mountains, visitors on tour with Mr. Graham were serenaded by the Zedashe ensemble, which sang songs with harmonies as pungent as the local cheeses.