Standard German phonology
In German, these two sounds are allophones occurring in complementary distribution. The allophone  occurs after back vowels and  (for instance in   'book'), the allophone  after front vowels (for instance in   'me/myself') and consonants (for instance in   'fear',   'sometimes'). (This happens most regularly: if the  in  is pronounced as a consonant,  represents ; however if, as often happens, it is vocalized as , resembling the vowel , then  may represent , yielding .)