Gnu-zoo merger

The gnu-zoo merger is the merger of /u/ and /ʊ̝ /

Some Scottish English speakers distinguish the vowels in "zoo" /zu/, "moon" /mun/ and "boot" /but/ from the vowels in "gnu" /nʊ̝ /, "scuba" and "tutu".

/ʊ̝ / is a vowel in between /ʊ/ and /u/