Orthodox Jews do speak the name(s) of G-d in prayer and formal readings of the Torah, as well as when reciting blessings and during other serious occasions. The names are simply not for everyday use and so most of the time we say Hashem (literally "The name" from the Hebrew word shem, a name). We also cannot write any name of G-d (again, we write Hashem, which is abbreviated as the Hebrew letter hay with an apostrophe) except on a Torah or in a prayer-book or something of that nature. Any piece of paper with a name of G-d on it cannot be thrown out or destroyed, it must be buried in a place called "shemos" and allowed disintegrate on its own. I have never heard that the pronunciation for this being lost. When it appears we substitute a different name of G-d, Ado. Anyhow, no Orthodox Jew would ever give this name to their child. The child would be forbidden to say his/her name, couldn't write his/her name on a test paper.
No one uses Yahweh as a name, just as children aren't named God or Allah. This is a site about the history of names, not about appropriate names to give a child.
The Jews (and hopefully Christians) consider/ed God too holy to look upon, speak His name, ect. Isaiah says, "Woe is me, for I am a person with unclean lips and live with people that have unclean lips, and I have seen the LORD." The Jews came up with a substitute for "Y----h" (I will speak the name if I think it beneficial, but prefer to respect our Lord). They came up with "Jehovah", or "LORD", which is different from "Lord". You will see it all through both Testaments. God is refered to as "Lord", then as "LORD" for some extra-special or important verse/passage. "LORD" (all capitalized) meant "Y----h", just as Jehovah does.