What is the proper way to train a child to recite a Beracha?

Clearly, if the adult and child are both eating or drinking, and they must both recite the same Beracha, the adult should simply the Beracha slowly, word-for-word, with the child. Thus, for example, if a father is drinking coffee and the child is drinking water, and the child needs help reciting the Beracha of "She’hakol," the father should recite the text of the Beracha word-for-word with the child, and then they each drink their respective beverages.

But what should the father do if he is not drinking, and the child needs him to dictate the words of the Beracha? Is the father allowed to recite the full text of the Beracha with Hashem’s Name?

In a case where the child can be prompted to recite Hashem’s Name, such that the father can help the child without reciting the Name, this is the procedure he should follow. Meaning, he says for the child "Ado," and the child will then understand that he needs to recite "Ado-nai." And he does the same for "Elo-henu." However, if the child does not even know enough to understand these hints, then the father may recite the full text of the Beracha with G-d’s Name to help the child. Hacham Ovadia Yosef rules (Yalkut Yosef, English edition, Berachot, p. 259) that since the parent has an obligation to train the child in Misva observance, he is allowed for this purpose to recite the complete text of the Beracha. Hacham Ovadia goes even further, applying this ruling to other children, as well. Since one is responsible on some level for the Misva training of all children, he may recite the full text of the Beracha to train even other children. For that matter, if one is with an adult who needs help reciting a Beracha, such as somebody who is learning to become observant, then in this case, too, he may recite the full text of the Beracha.

Summary: If a person is with a child or even an adult who needs help reciting a Beracha, and he will not be able to help without reciting the full text of the Beracha including G-d’s Name, he may recite the Beracha, even though he will not be eating or drinking.