There is a machloket among the Rishonim about the nature of the obligation of chinuch (education) for children at the appropriate ages to perform mitzvot that they will eventually be obligated to do as adults. Rashi[1] maintains that the child is not personally obligated, even on a Rabbinic level, to perform mitzvot; rather, his father is obligated to train him to perform the mitzvot. Tosafot[2] argues, however, that the child is personally obligated in the mitzvot, albeit on a lower level than an adult. There is an arguably related machloket as to whether the chinuch mitzva performance must meet formal halachic standards or whether it must simply be done in an educationally effective manner, so that the child will fulfill the mitzva properly when he becomes an adult.
This machloket is reflected in the following typical case. An adult must own the lulav and etrog that he takes on the first day of Sukkot[3] (two days outside of Israel[4]). There is therefore a problem sharing a lulav and etrog set with one’s child on that day, because when one transfers ownership to him, the child is not halachically capable of transferring ownership back.[5] The Shulchan Aruch[6] suggests that the child should use the lulav and etrog without the father transferring ownership to him, thereby avoiding the problem. The Mishna Berura[7] cites two opinions as to whether the child has fulfilled his obligation under these circumstances. Rav Moshe Feinstein[8] explains that the two opinions depend on our fundamental question: Is a child obligated to perform his mitzvot with all the regular detailed requirements that an adult needs, including the imperceptible requirement of ownership? In that case, the mitzva was not done properly, as a child must own the lulav and etrog, like an adult. Or do we hold that a child must perform the mitzva only so that he will know what to do when he is older, such that the imperceptible lack of ownership due to his youth is not a problem? Rav Feinstein demonstrates that the former approach to the obligation, placing the responsibilities of an adult on the child, is correct.
Turning to our case, according to the formal approach, there is no minyan without ten men, and the group of children is not authorized to say devarim shebekedusha,[9] such as Barchu, Kedusha, and Kaddish.[10] This case is different from that of lulav, where children are obligated in the mitzva. Here, there is no quandary for them to omit these special elements of tefilla, because children are not obligated to daven with a minyan. In fact, even according to the practical educational approach, having the children recite Barchu and the like is not a fulfillment of chinuch, as the educational element includes having a child becoming accustomed to recite devarim shebekedusha specifically with a real minyan.
One might argue that the general idea of getting children used to doing mitzvot, without necessarily fulfilling a formal mitzva of chinuch, justifies their reciting berachot and portions of tefilla that may not be recited voluntarily. The Shulchan Aruch[11] rules that one is allowed to have children practice making berachot even in a manner that is usually considered l’vatala (in vain), and an adult can answer amen. The Mishna Berura[12] adds that not only may the child pronounce HaShem’s Name in an educational, non-beracha context, but the person teaching him can do so as well. It thus seems that one can teach children to recite devarim shebekedusha outside the context of a minyan.
However, this applies only when it is necessary to teach those specific elements to the children. One may not establish on a regular basis a “make-believe minyan” for children when they could learn what needs to be done in far fewer sessions. In fact, the most appropriate way to get the children used to a minyan is to enable them, when they are close to becoming bar mitzva, to join with adults or peers who are already bar mitzva. Staging a minyan on a regular basis is both halachically problematic[13] and educationally unsound.[14] (Exceptional circumstances can be discussed on an individual basis.)