There are non – Jews who see the Shem Havayah (Yud – Hei – Vav – Hei) written with vowels and claim that these vowels hint to the exact pronunciation of G – d’s highest Name.
Vowels can be found below various Hebrew letters. Most of us know them from our Ulpan because these dots made it much easier to learn Hebrew. At least we knew how to pronounce certain words while we were reading. Hebrew is a rather complicated language and the way of spelling it totally different from many other languages.
However, vowels underneath and above Hebrew letters don’t only have the task to make words more obvious in case the Aleph or Vav or another letter is left out. The vowels in connection with a couple of other symbols underneath and above Hebrew letters are extremely important when it comes to the original Torah text.
Above you can see an example of a text taken from the Bircat HaMazon (Grace after Meal). Neither my Artscroll Sidur nor my Artscroll Torah show the Shem Havayah with any vowels.
The highest Name of G – d was only used in the Temple by the Cohen HaGadol. In those days, the High Priest still knew how to pronounce this Name in a proper way. After the destruction of the Second Temple, the precise pronunciation got lost. Until today, we Jews are not allowed to pronounce this Name but rather replace it with A – do – na – i or Hashem (the Name). However, there are a lot of Christians who think that they have the right to say the Name out loud, even though it is a false pronunciation. For instance, we all know the sect called the … Witnesses.
Pronouncing the Name is strictly forbidden because it is a Chilul Hashem (desecration of G – d’s Name). I read that the Shem Havayah does actually appear with vowels from time to time but the vowels are not always the same. The reason would be that Gentiles have to be prevented from erasing G – d’s Name which is an Issur Deoraita. There is supposed to be something in the Shulchan Aruch about it but, so far, I haven’t found it.