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 .)