However, there has been some critique of the transliteration schema. Some users state that the unmodified letters are straightforward to read (except for "*"=dhaal and "E"=ayin, "v"=thaa), but the transliterations of letters with diacritics and the harakat take some time to get used to, for example the nunated ' appear as "N, F, K", and the ' ("no vowel") as "o". "" is "p". The difficulty probably has happened because usually the Buckwalter Transliteration is used and/or presented without the rationale behind the letters. Though those particular letters seem to be random they are actually mnemonically linked to the original letter.