A teacher creates new specialists.
A teacher will take a specialist and a peasant and he can train that peasant to become the same type of specialist as the specialist used. He can train the student up to a level equal to the average of one half the level of the teacher and the full level of the original specialist, rounded down.
The time involved is equal to 1 turn plus one half the cumulative level of the new specialist. The entire time that the student is in training, the teacher, the peasant, and the specialist are unavailable for other functions.
For example. A level 6 teacher takes a peasant and a level 5 Armorer. The teacher can train the new armorer to a maximum level of 4 ((6/2 + 5)/2). The time required would be 6 turns. 1 + ((1 + 2 + 3 + 4)/2).