I do this with a few words and I am no salafi. My reason is so that I can make the word as phonetically correct. for example the name Hamid. You can say it in two different ways, one stretching a 'a' sound and the other stretching the 'i' sound. when you add an extra 'a' or a double 'e' it makes it a whole lot easier to pronounce correctly. Same with the word Hadith. Stretching the 'a' makes it into one word, and stretching the 'i' makes it into a different word.