In any case, he would be strictly forbidden to speak till his teacher gave him formal permission to do so.
Half-an-hour in the morning, and half-an-hour in the afternoon would probably be set aside for the language lesson.

For so many weeks or months the child would be strictly limited to words of two or three letters.

For so many more weeks or months, to words of four or five letters.

Things which had names of more than the prescribed number of letters would be kept away from the child; or, if that was impossible, he would not be allowed to talk about them.

For half a year perhaps he would be limited to the use of nouns and verbs.
Prepositions might then be introduced into his vocabulary; and, later, adjectives and adverbs.