The digraphs and are generally pronounced , but are fronted to before front vowels ( and ) and tend to be pronounced before the back vowels ( and ). When these digraphs are preceded by a vowel, they are pronounced and before front vowels ( and ) and before the back ( and ). The digraph may be pronounced in some words ( before front vowels and before back ones). The pronunciation for the digraph is extremely rare, but could be heard in literary and scholarly words or when reading ancient texts (by a few readers); normally it retains its "original" pronunciation only in the trigraph , where prevents the sonorization of by (hence ).