There is dialectal and allophonic variation in the realization of /ʋ/. For speakers who realize it as [ʋ], Rubach (2002:683) postulates an additional rule that changes any occurrence of [w] from glide insertion into [ʋ]. Rubach, Jerzy (2002), "Against subsegmental glides", Linguistic Inquiry, 33 (4): 672–687, doi:10.1162/ling.2002.33.4.672, S2CID57566358
There is dialectal and allophonic variation in the realization of /ʋ/. For speakers who realize it as [ʋ], Rubach (2002:683) postulates an additional rule that changes any occurrence of [w] from glide insertion into [ʋ]. Rubach, Jerzy (2002), "Against subsegmental glides", Linguistic Inquiry, 33 (4): 672–687, doi:10.1162/ling.2002.33.4.672, S2CID57566358