Oh boy. There's a lot to this topic. Just a few basic points to start.
G-d has two types of names: Names (Shemot), and titles (Kinuyim). Using the analogy of a person a name is like that someone's name is John. Then John can have titles like: Doctor, the kind one, the good basketball player etc. Titles refer to qualities of the person. Essential names refer to the person himself. So if I call him John, I'm referring to his whole being, not just one aspect of him.
So too, G-d is referred to in the Bible with titles sometimes like: "Rachum" (mercifull one) "Erech Apayim" (the One who is slow to anger). These refer to G-d's qualities. Then G-d has essential names that refer to G-d Himself spelled: Y(Heb. yud)-H (hay)-V (vov)-H (hay) and A (aleph)-D (dalet)-N (nun)-AI (yud).(but this get's complicated because these can also sometimes be titles)
Now there are a lot of detailed laws in the Talmud and in the later commentaries when you can use these names. Here's just a few basics:
-One of the names which is 72 letters long names can only be said once a year by the high priest.
-Most (maybe none?) can never be said in the bathroom.
-It's more lenient if you use the English version of the name but some restrictions still apply.
-It's more lenient if you're using a "title" instead of an "essential name".
-It's always more lenient if the name is being used as part of a prayer as opposed to being used casually.
-Most people avoid all these issues by not using any name at all but just using the Hebrew word "Hashem" which just means "the Name".
So I guess to answer you're question, it depends, who is saying it, when, where, why, how, and in what language.