In describing the observance of Hakhel, when the entire Jewish nation should gather in the Beis Hamikdash, the Holy Temple, to hear the king read select portions of the Torah, the Rambam makes particular mention that “even converts who do not understand” the Holy Tongue, in which the Torah is read, must attend the assembly.
The source for the Rambam’s unique emphasis on the attendance of converts who do not understand the reading of the Torah can be found in the words of the verse that enumerates the attendees: “The men, the women, the children, and your foreigner who is in your gates.”
The Torah alternates between a number of expressions when referring to converts, including “The foreigner who dwells in your midst,” “Your foreigner who is in your camp,” and “Your foreigner who is in your gates.” The simple difference between these expressions is that the terms “foreigner who dwells in your midst” and “foreigner who is in your camp” imply that the convert has long been part of the Jewish community, whereas the term “foreigner who is in your gates” can be interpreted as referring to a convert who is just barely “in the gate”—he has only recently joined the Jewish community.
Since the Torah mentions the convert’s participation in the Hakhel assembly specifically using the expression “the foreigner that is in your gates,” the Rambam understands that even the newest converts, for whom the original language of the Torah may still be foreign, are an integral part of the Hakhel assembly.
—Sichos Kodesh 5735, vol. 1, pp. 50–51; Likkutei Sichos, vol. 36, p. 245