My experience (at least in the Orthodox Ashkenazic community) is that it is common knowledge that we may not say Elohim in everyday speech. On the other hand, it seems like in many cases in Tanach or Talmud the name Elohim or similar is used in conversational terms or at least not directly in a blessing.
Is this true Halacha as many Ashkenazim appear to think it is, is it more of a minhag that has the force of Halacha, or is it not true?
And if it is forbidden as many seem to think it is, then why can't we say God's name? Also is there one name that is forbidden while other terms are not? For example many places and names include "el" in them and that seems to be fine.
Also, in practice, if you speak Hebrew and want to teach a child about God, do you actually use a fake word like "Elokim" to discuss it?