Q. If one is speaking words of Torah in a conference or at a celebration and all or even some of his listeners are people who usually one does not expect that they said Birchat Hatorah on that day, is he permitted to continue? Maybe he should recite for them before the bracha? Should he ask one of them to recite it now?

A. On similar question 468 we wrote: “The widely accepted custom is that it is permitted to say or teach Torah to people who have not recited the prior brocho to its study. Throughout generations we have witnessed Gedolim speak at simchas or say eulogies when many of the presents were not necessarily frum yet.

The reason why we don’t incur in the prohibition of Lifnei Iver (placing a stumbling block before the blind, Vayikro 19:14) or at least of Mesayea ledvar aveiro (helping someone perform a prohibited act) is explained by Horav Silverstein Shlit”a quoting Horav Eliashuv zt”l (Aleinu Leshaveach 5 p.636) namely that unlike Birchos Hanehenin (brochos on food etc.) where there is an actual prohibition of eating without a brocho, there is no proscription of learning Torah without first reciting its brocho. He also adds that it is likely that the yet non-frum listener may not have any intention for complying with the mitzvah of learning Torah so no brocho would be required anyway.

Horav Shlomo Miller Shlit”a agrees with the above and added that there may be even a prohibition on reciting birchas Hatorah exclusively for them, since they do not yet have emunah the blessing may be in vane.”

As far as asking one of them to recite the brocho, Horav Aharon Miller Shlit’a mentioned that since he does not yet normally recite this brocho, its value may be questionable
.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller, Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a