The Quilisma, an ascending three note neum, is distinguished by the middle note, which looks like a zigzag pattern. As its shape suggests, it is an energy note, leading quickly to the top pitch of the pattern. The first note is slightly lengthened, as to gather energy before ascending through the next two pitches.
Any note or series of notes can be slightly lengthened by adding a line over them, called an episema. We usually find a dot on notes before a full or double bar. We always need to keep in mind, however, that chant is based on speech rhythm. so any lengthenings need to be treated the same way we would pause or stop if we were speaking the text, or adding emphasis. It’s not a metric doubling of the length.
Another special sign is called the liquescent. You’ll notice in the example above, that the second note is smaller. It means that more attention needs to be given to a particular consonant – usually an l, m or n. We actually hum through those consonants on the particular pitch that’s shown with the small note. The word hosanna is often sung using the liquescent. The little humming note coincides with the n of the middle syllable, and we actually sing that sound on the indicated pitch before releasing to the na of the final syllable. It is so evident in looking at these ancient signs, that much detail was given to the pronunciation of the text!