There is a Name of God that is considered the true Name in the Jewish tradition. It is called the Tetragrammaton, the Name with four letters. The letters are the Hebrew equivalents of Y, H, V (or W), and H. There are no vowels in this set of letters, so it is reasonable to conclude that the Name cannot be pronounced. However, this isn’t true.
The Hebrew alphabet does not contain vowels. Written words only have the consonants. Speakers of Hebrew know what vowel sounds are required, so they automatically pronounce them when they read Hebrew words.
In some cases, dots (known as ‘points’) are added to the consonants to indicate what vowel sounds are needed. These points are not part of the alphabet; they were devised to help people, especially those who don’t speak Hebrew, know how to say the words.
This Name of God is not unpronounceable. It is simply prohibited to utter it. According to one tradition, this Name was only spoken once a year, during the Day of Atonement – and only by the high priest, within the Holy of Holies of the Temple. Another tradition says that the Name was pronounced daily at the Temple. When the Temple was destroyed, the Name was no longer spoken. However, knowledge of how to pronounce the Name has been preserved.