Sensitive period
The Montessori sensitive period concerns moments of particular readiness in children to work with new things, to acquire new skills.
Dr. Montessori noticed that in a child's development there are particular periods in which the child is especially sensitive and ready to acquire specific knowledge. These phases occur only once and are not repeated. However, this does not mean that at other times the child will not learn it, but it can be much more difficult.
A child in the sensitive phase is extremely interested in a given topic, even desires certain exercises. The main duty of the teacher and parent is to observe this particular sensitivity, provide them with proper support and not interfere.
In Montessori's literature, we can find, among others, such sensitive phases in a child:
This phase concerns all aspects of motor skills, the entire physical development of the child. During this time, children in a Montessori kindergarten most often choose materials from the practical life section, including exercises for both fine and gross motor skills, or sensory materials, which often require the child to walk at least 10 “lengths” around the room.
Between 2.5 and 4.5 years, there is also time for special improvement of motor skills. Time for walking, running, balancing, constant activity, through purposeful repetition of activity.
The period between 4 and 5.5 years of age is the time when, according to Maria Montessori, the right time comes to learn numbers. In our kindergarten, mathematical materials are built from concrete, not abstractions, which definitely makes it easier for children to understand them.
Up to about 3 years old, children learn polite behavior by observing their closest relatives and imitating them. In the following years, however, there is a special sensitivity to this and readiness to learn and understand the rules of good behavior.
A child is sensitive to speech already in its mother's womb. Later, after birth, it is interested in every sound from the environment, recognizing voices, and later understanding the meaning of words, which will allow it to communicate.
There are different varieties of language - spoken, written, read. Montessori observed that the preschool period is the first period in which a child is sensitive to writing. It usually covers the period from 4 to 4.5 years old. Right after that, around 4.5-5.5 years old, the child often begins to read, spells words and combines single words into words.

