Most Montessori materials are demonstrated in a mostly silent manner.  One exception is the three period lesson used to introduce a new concept, such as vocabulary or a letter sound.  The three period lesson is used to teach, then reinforce the teaching.  Some materials that use a three period lesson are the geometric solids, sandpaper letters, nomenclature cards, and geography terms.   To begin, the teacher lays out 2-3 items, such as the cube, sphere, and cylinder from the geometric solids basket.  She points to one (we will select the cube) and says, “This is the cube . . . cube.”  Then continues pointing and naming, “This is the sphere . . . sphere. This is the cylinder . . . cylinder.”  She may then leave the child to explore the material,or continue on to the second step.  The second step is asking the child to identify a given item.  “Please show me the cube.”  If the child accurately and easily identifies the cube, sphere, and cylinder when asked, the teacher will then point to a solid and ask, “What is this?”  Sometimes a teacher may introduce items on several occasions before moving on to periods two and three to ensure that children are successful and that they have truly mastered the term.  For more information about the three period lesson, you may visit these links:

Montessori For Everyone – The 3-Period Lesson

infoMontessori – The Three Period Lesson Sensorial & The Three Period Lesson Language  you may also view a video demonstration of The Three Period Lesson

North American Montessori Center – The Three Period Lesson – A  Key Part of the Montessori Method Explained