Incantations/Spells
詠唱・呪文 - Eishou/Jumon
The operation needed to run thaumaturgy.
When using a form of thaumaturgy already stabilized/established as a first-rate school, an already determined process has to be gone through. Part of that process are incantations. Procedure-wise, incantations would be the "application" part in a system of application, acceptance, examination, and issuance.
While incantations themselves are just part of the procedure in regards to execution of thaumaturgy having large systems, in the case of execution of personally-styled thaumaturgy, they have high effect as means of self-hypnosis. To turn on and run one's internal circuits effectively, incantations were created.
Incantations are chanted not to the world but to one self. The reason why incantations may vary between magi even though the spell is the same is reflective of the difference in the personality of the caster.
Those incantations that are cast at the world and not one self are "grand incantations" and fall in the category of great rituals. Use by oneself is said to be impossible.
As spells already have predetermined abilities, no matter which magus uses it, the force of the spell won't change. The only thing that differs are the incantations. The incantations of a spell are what activates the thaumaturgy inscribed in one's own body and also illustrates the nature of the magus. This is because as long as the necessary meaning/set keyword are included for that spell, the details of the incantation are up to the magus' personal tastes.
The incantations of those magi that are easily intoxicated with themselves are long. However, by adding more meaning to it, the power of the spell increases. The stronger the self-hypnosis, the better a magus can draw power from himself (probably in terms of maximizing the power of circuits). It's best to find a good balance between meaningful length (words that would enhance the mind), reduction of rhyme, and quickness of pronunciation. For Shirou, Archer's UBW incantations are the ones that are best suited for raising success rate for tracing overall. Changing the words of the incantation doesn't mean much; what really matters is the meaning behind them.
Single Actions - Requirement is to only pass energy to activate. Gandr shots and mystic eyes are single action spells. Instant spells.
One-Line - Fixing an effect within oneself, ie, Rin activating her crest to cast a One-Line spell for either removing a sigil, or for gravity adjustment and weight reduction.
Ten-Count - Instant Contract. A simple ritual. Necessary for high thaumaturgy (rank A spells or higher). Casting time is typically one minute for a fully-trained magus and 30 seconds for one with high speed incantations). Consisting of ten or more lines, which may consist of one word per-line at the bare minimum.
Archer and Shirou's incantations are over 5 lines long and are close to Ten-Count types. Probably referring specifically to the UBWs.
The majority of Caster's spells fall into the One-Line category, but speed is even faster or at least just as fast as Single Action spells (No Action) and power-level is no less than that of Five-Line spells. Also, as her spells are Divine Words, they do not fall into the normal categories and thus the conditions of Anti-Prana B, C, and D do not apply to her.
It should also be noted that despite how long Archer's UBW verses might have actually been, gamewise, the completion of the spell was VERY short.
Note that for long incantations, before the spell is actually completed, there will normally be an observable effect on the outer world (with the exception of Reality Marble incantations or any other spells that don't activate already existing "programs").
Anything longer than a Ten-Count incantation is probably considered an actual ritual.