So far you have studied only quantitative symbols. Interval symbols are quantitative symbols; they tell you to go up or down by how many pitches. Some symbols are qualitative. They tell the chanter how to execute a pitch. Some interval symbols are both qualitative and quantitative symbols. The best way to learn how to execute qualitative symbols is by chanting with a traditionally trained chanter over time. In the absence of this, one can listen to recordings and follow along in a score. Still, there are two basic qualitative symbols that you should learn at the beginning, as they serve to bring out the text in brief hymns. These are the petaste and the psifiston.
A petaste is both qualitative (indicating emphasis) and quantitative (indicating Up 1). The simplest way to add emphasis with a petaste is to execute the interval called for and then to flutter up to the next pitch and back down again. In future lessons, you will see that the petaste can be used in combination with other interval symbols to put emphasis on those pitches as well.
A psifiston is only a qualitative symbol. You will only see a psifiston in combination (placed under) an interval symbol. The simplest way to add emphasis for a psifiston is to slide into the pitch.
The kentemata is a new interval symbol. It is only quantitative (Up 1) and not qualitative. However, you will only find the kentemata when the text of a hymn is slurred; one syllable is drawn out over two pitches.