Durations of acoustical segments were measured in four Estonian folk songs sung by a single performer, consisting of 152 verse lines, eight syllables each, with one note in the melody normally corresponding to one syllable in the text. The results were analyzed with regard to three aspects: notation, meter, and speech prosody. Three songs out of four are notated as isochronous sequences of 8 eighth notes per each verse line; in one song, certain pairs of eighth notes are replaced by a dotted eighth note plus a sixteenth note. The results revealed a complex interaction between meter, musical rhythm, and speech prosody. Variations in durations of sound events reflect the Kalevala meter on which the songs are based, with average rises in a foot being acoustically longer than falls. The duration differences between rises and falls are reduced in the socalled broken lines, which contain monosyllabic and trisyllabic words and allow for accommodation of short stressed syllables at a fall of a foot as required by the meter. Semantically relevant oppositions of wordinitial short-long and long-short disyllabic units in speech are not kept completely intact in folk songs. Short-long disyllables are treated in a different manner by the performer, depending on whether their initial syllable occurs at a rise or at a fall in a foot.