In the villages a horo was very often danced to singing, not to a band. In 1930 Vasil Stoin, the great collector of Bulgarian song, published a songbook for village readers, Народна пѣснопойка, and under 62 of its 271 songs he printed four words: Пѣе се на хоро — sung at the horo. Two more are horos by name. All 64 are here, transcribed from the public-domain scan, engraved with the words under the notes, ready to sing, play and download.
Source: Васил Стоин, Народна пѣснопойка (Sofia: Държавна печатница, 1930), scanned on the Internet Archive. Public domain: published 1930; Stoin died in 1938. Each song is transcribed exactly as printed — notes, words and spelling of the time — and checked bar by bar against the page. Melodies are the first verse, as the book prints them.
At the back of the songbook Stoin explained, for readers who knew only 2/4 and 3/4, how to count the meters that make Bulgarian music limp. His words, in English, a little shortened.
The most important feature of the rhythmic build of Bulgarian folk music is the lengthened beat (удълженото време). It holds exactly one and a half beats — it is written with a dot after the note — and it creates our irregular meters. In our folk melodies it comes once in a bar, after or before one, two or more normal beats, or twice, around them.
So the top number of an irregular meter is written as the sum of its half-beats: one normal and one lengthened beat, two and a half beats, is written 5; two normal and one lengthened is written 7, and so on. And because most of our folk melodies in irregular meters are dance-leading songs, performed very fast, the beat in these meters is written with the sixteenth: two sixteenths for a normal beat, three for a lengthened one.
5/16. Two beats, a normal and a lengthened one. Beat time with your foot and you strike twice in each bar, but the second strike is held longer. To hold it exactly one and a half beats, count едно-две on the first (one as the foot goes down, two as it lifts) and едно-две-три on the second. Count perfectly evenly, slowly at first, faster bit by bit, and at last replace the numbers with the syllables та and ра — our number words have too many sounds to say fast: та-ра, та-ра-ра. In this songbook the lengthened beat of 5/16 is always the second. 5/16 with the second beat lengthened is the paidushko horo.
7/16 comes in two forms: with the third beat lengthened (2+2+3) and with the first (3+2+2). 7/16 with the third beat lengthened is the ordinary ruchenitsa.
8/16 has three beats, the first and last lengthened (3+2+3): the song Дафино вино. 9/16 has four beats, one lengthened — the fourth (2+2+2+3, the song Боли Яна бѣло гърло) or the second (2+3+2+2). 14/16 is 5/16 and 9/16 joined; practise its two halves one after the other: the song Мамо, речи тату.