The common folk are continually singing as they work. Why? What effect does this have? Why do they spend the energy? And why are they singing similar songs across the land? Because those songs are actually chants, special songs that induce magical effects. These chants gain strength from massed voices--the choir is greater than the sum of its voices. Each chant is simple, but blending voices requires effort and trust. Only the most disciplined groups can reach the full strength of a chant, even though most societies use chants on a smaller scale.

Chants can be divided into plain chants, which only have effect while they're being sung but do not require blood sacrifice, and high chants, which have extended, more powerful effects but require some form of blood sacrifice as a catalyst.

All chants have a scaling factor and a limit--the scaling factor explains how the effect increases as you add new voices to the chant, while the limit sets how many voices can contribute and thus the maximum effect of the chant. Note: these are empirical limits and are not to be taken as exact figures. They're more indicative of the numbers of voices needed to cover particular areas.

Plain Chants

These are the songs sung as the farmers work their fields, as the herders watch their cattle, as the teamsters guide their wagons and barges. Everyone knows a few chants that they employ to aid them in their daily work. A herder might not be expert at the farming chants, but would probably know the basics. A teamster might know the herding ones at a basic level, but be less familiar with the farming chants. Etc.

The effects of plain chants last only moments after the chanting stops, so they're sung continually or in the round. Usually, their effects cap at about 5-10 voices, so large groups tend to sing different related chants. This makes the normal village life quite noisy.

Plain chants tend to be a single set of nonsense phrases or a hummed melody of a few measures. These are sung endlessly, taking short breaks to protect the voice. Volume isn't important, but enunciation is.

Here are a few examples of plain chants and their effects:

Weeder’s Plaint
Base area: 5’ diameter (about arms length)
Scaling: area doubles for each new voice.
Limit: 80’ diameter (5 voices within the area)
Effect: Unwanted plants within the affected area glimmer slightly and their roots become loose in the ground, making them easy to pull. The singer’s intention defines what plants are unwanted. To merge together, voices must have the same intention.

Bug-me-not
Base area: 1000 creatures within 300 feet.
Scaling: Number of creatures increases by 1000 and range increases by 100 feet for every voice.
Limit: 5000 creatures, 700 feet.
Effect: Biting insects are discouraged from landing on or attacking affected creatures.

Preserver's Anthem
Base area: 100 pounds of edible material within hearing distance.
Scaling: affected mass doubles for each new voice
Limit: 16000 pounds of edible material.
Effect: Spoilage is suspended while the chant is ongoing.

Lament of the Ox
Base area: 2 creatures in hearing distance
Scaling: affected number of creatures doubles for each new voice.
Limit: 32 creatures.
Effect: The affected creatures can move at a normal pace while dragging or lifting up to one and a half times as much as their normal capacity. [Mechanical note: the default is that you can lift/drag/pull as much as 2x your normal capacity, but your speed drops to 5' while doing so. With this chant, you can pull/lift/drag up to 1.5x as much without penalty, but more than that still causes penalties and your maximum doesn't change. This does stack with a vehicle, so draft animals can pull more weight at a normal speed.]

High Chants
These hymns are sung by a whole community as part of a festival. Unlike plain chants, they have a lasting effect but require some form of blood sacrifice such as a chicken or a lamb or other small animal. Willing sophont sacrifice is only done in extreme circumstance, and unwilling sacrifice is abhorrent in all civilized areas, as it contaminates the ground with abyssal-tainted anima (causing an increase in disease, damaged plant growth, and possibly causing spontaneous generation of undead or other monstrosities).

High chants also require a certain number of voices in active harmony and require a leader. They take the form of a challenge-response cycle or fugue-like variations on a theme and tend to be much more complex than plain chants.

Examples:

Pestbane Hymn
Minimum 20 voices
Chanting time: 1 hour
Base area: 500’ radius (~18 acres)
Base duration: 32 days (1 month)
Scaling: area doubles and duration increases by 1 month for every 20 voices added. .
Limit: 4000’ radius (1.8 sq miles), 4 months
Effect: Pests such as plant-eating insects, birds, or small beasts are discouraged from the affected area for the duration. Unless driven by magic, they will not willingly enter the area and will leave as soon as possible. The plant life in the region tastes bad to them.

Anthem of Safe Birth
Minimum 10 voices.
Chanting time: 1 hour
Base area: 100 animals of one type (sheep, cows, chickens, etc).
Base duration: 1 week.
Scaling: +10 animals per voice. Duration increase by a week for every 10 voices.
Limit: 500 animals., 6 weeks.
Special requirement: sacrifice must match animal type.
Effect: Affected animals have birthing-related complications reduced by a significant amount. Newborn animals come out much more resistant to disease and gain weight faster.