Shalom. Can a Jewish male (Orthodox) person without a Semicha teach other males publicly? I have seen this a number of times, whether an assistant Rabbi or just someone who knows the subject well. Assuming that there are no specific halachic rulings involved, are then any limits to what one can teach others? The reason for this question is that I heard that if one has good talent & knowledge, one has to teach other Jews, as it is an important Mitzvah; especially when it gives them enlightenment and brings them closer to G-d. What would be a source for this? Thank you.
Any Jew may teach torah, as long as he knows the material well, and will teach it correctly. Teaching torah is part of the mitzvah of learning torah, in which all males are commanded.
On the other hand a person may not paskin a halacha for others unless he has reached the correct level.
Rambam Sefer Hamitzvos Assay 11, See Midrash Shir Hashirim on 8-12 on the words Haelef Lecha Shlomo, in the name of R’ Alexsandrei, that one doesn’t get full reward for torah until he teaches it to others. Also see Rambam Hilchos Talmud Torah 5-4.